Chapter 1. The Language at a Glance#

What is Lojban?#

Lojban (pronounced LOZH-bahn) is a constructed language — an artificial language deliberately designed rather than evolved naturally over centuries. It has been in development since 1955 and has been used for translation, original prose, and poetry.

What makes Lojban unusual among constructed languages:

• Unambiguous grammar: every sentence parses in exactly one way. There is no vagueness about sentence structure.
• Phonetic spelling: every letter has exactly one sound range. You read what you hear, and you hear what you read.
• Predicate-based: all words, whether they translate as nouns, verbs, or adjectives in English, work the same grammatical way. There are no special noun or verb forms.
• Culturally neutral: the root vocabulary was derived from the world's most widely-spoken languages (Chinese, English, Hindi, Spanish, Russian, Arabic) according to speaker population, with sounds and forms adjusted to be unambiguous.
• Expressive: some 1,300 root words combine to produce millions of derived words, and the grammar handles tense, mood, evidentiality, logic, and emotion systematically.

You don't need to know logic or linguistics to learn Lojban — but if you enjoy precision, you'll be in good company.

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The Alphabet#

Lojban uses the standard Latin alphabet minus three letters (h, q, w), plus three punctuation-as-letters: the apostrophe ('), the period (.), and the comma (,).

The full Lojban alphabet in order:

' . , a b c d e f g i j k l m n o p r s t u v x y z

Alphabetical order follows ASCII order, which makes computerized sorting straightforward.

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Vowels#

Lojban has six vowels. Five are common in content words; y appears mainly in compound words and names.

All Lojban vowels should be pronounced clearly and distinctly. There are no silent vowels and no vowels that "reduce" when unstressed — except y, which is always the schwa sound.

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Consonants#

Most Lojban consonants are pronounced as in English, but several need special attention.

Two English consonant combinations become two-letter sequences in Lojban:

• The ch sound of church is written tc (IPA [tʃ])
• The j sound of judge is written dj (IPA [dʒ])

Doubled consonants never appear in Lojban. All consonants must be clearly distinct from their neighbors.

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The Three Special Characters#

The apostrophe (') represents a short h sound (IPA [h]). It appears only between vowels, where it separates them into two distinct syllables while keeping them in the same word. Think of it as a "soft h" — a gentle breath between vowels.

The period (.) marks a mandatory pause or glottal stop (IPA [ʔ]). Every word beginning with a vowel must be preceded by a pause, and every word ending in a consonant must be followed by one. Periods are technically optional to write (the rules already require the pauses), but writers include them as a guide for readers.

The comma (,) marks a syllable break within a word without any pause — the opposite of the period. It is used mainly in names that have adjacent vowels that should not merge into a diphthong, or to mark syllabic consonants (l, m, n, r). Commas are never required and never change a word's identity.

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Diphthongs#

A diphthong is two vowel sounds pronounced as a single syllable. Lojban has four diphthongs freely used in ordinary words:

Ten more diphthongs exist but appear only in names and borrowed words:

When two vowels appear together without an apostrophe, they form a diphthong. With an apostrophe between them, they are two separate syllables. Compare:

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Stress#

Lojban stress is regular and predictable:

1. Stress falls on the second-to-last vowel (not syllable — vowel) in every word, with one exception: if that vowel is y, skip back to the third-to-last vowel.
2. Single-syllable words carry no stress.

Examples:

In practice, stress in common short words becomes natural quickly. The key rule to remember: stress the second-to-last vowel, never the last.

Capitalization is only used in names to indicate non-standard stress (stress that does not follow the default rule). For example, the Lojbanized form of Josephine is written DJOsefin. to show that the first syllable is stressed, not the second-to-last.

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Reading Lojban Aloud#

Lojban is a phonetic language: every word is pronounced exactly as written, and every spoken sound maps to exactly one written form. There are no silent letters, no irregular spellings, and no exceptions.

A few practical tips for beginners:

• Vowels are long and clear. Don't reduce unstressed vowels (except y).
• Each letter is one sound. The letters c, g, j, x each represent a single fixed sound — resist any English spelling intuitions.
• Consonant clusters at word beginnings are normal in Lojban. Words like klama (go), broda (some-relation), and spuda (respond) are typical. If you struggle with a cluster, a very short, quiet y-like schwa between the consonants is accepted colloquially.
• The period is a real pause. Don't swallow it.

Here are a few words to practice reading aloud:

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About This Book#

This book is a reader-friendly version of The Complete Lojban Language (CLL), the authoritative reference grammar written by John Cowan and published by the Logical Language Group. The original CLL is complete and precise — but it was designed as a reference, not a tutorial. Material there is organized by grammatical category rather than by what a learner needs first.

In this book:

• Material is ordered for progressive learning: you can start speaking simple sentences after Chapter 2 and reading basic texts after Chapter 8.
• Examples come from authentic translated Lojban texts wherever possible.
• Technical terminology is introduced gradually, with plain-English explanations first.
• All of the CLL's content is covered — specialist topics like the full tense system, mathematical expressions, and formal grammar appear in later chapters and appendices.
• Word definitions include simplified type annotations: (object), (event), (property), (proposition), (text), (number), (sound) — just enough to understand what each place expects.

Cross-references to the original CLL are noted where relevant for readers who want the authoritative technical detail.

How examples and cross-references work#

• Lojban in examples is usually in bold; glosses (rough English) are in italics on the following line or after an em dash.
• Blockquoted lines (>) are teaching examples unless labeled as corpus quotes or dialogue.
• Internal links use the form Chapter n. All cross-references in this book point to other friendly-cll chapters; the book is designed to be self-sufficient.
• Elision: terminators (ku, vau, kei, …) are often dropped when the parse is obvious; later chapters say when you must keep them.
• Terms: bridi (claim), sumti (argument), selbri (predicate) are defined in Chapter 2.
• Example integrity: Every Lojban example in this book is sourced from or adapted from the canonical CLL, the Learn Lojban course, or the corpora. When an example is adapted (e.g. a character name changed from la .alis. to la .teris.), the underlying grammar and place structure are kept identical. Examples are never invented from scratch.

Enjoy the language.

coi .lojban.
Hello, Lojban!

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Summary#

• Examples: bold Lojban, italic gloss; cross-links via /en/books/friendly-cll/; elision is normal in learner text; examples are sourced from CLL/corpus, never invented
• Lojban uses 26 Latin letters minus h/q/w, plus ', ., ,
• All pronunciation is regular: read what you see, hear what you read
• Vowels a e i o u are pure sounds; y is the schwa
• c = sh, j = zh, x = ch (Scottish loch), g always hard
• ' = breathy h between vowels; . = pause/glottal stop; , = syllable break without pause
• Stress the second-to-last vowel
• Four diphthongs in common words: ai ei oi au

Chapter 2. Your First Sentences#

The Central Idea: Relationships#

In Lojban, the sentence is a predication — a claim that certain things stand in a certain relationship. This unit is called a bridi (roughly: "predication" or "claim").

Every bridi has two parts:

• A relation construct called the selbri — this specifies which relationship holds.
• One or more argument terms called sumti — these specify who or what is involved in the relationship.

In English, we distinguish between nouns, verbs, adjectives, and adverbs. In Lojban, there are no such distinctions. The word prami can act as "love", "lover", "beloved", "loving", or "lovingly" depending on context — it always describes the same underlying relationship.

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Three Word Types#

All Lojban words fall into one of three categories:

Relation words (brivla in Lojban)

Words that express relationships. They always contain at least one consonant cluster (two consecutive consonants) within their first five sounds and always end in a vowel.

Examples: prami (love), klama (go/come), citka (eat), tavla (talk)

Brivla come in three subtypes — all grammatically identical, only different in origin:

A quick example of each:

ta cu klama le zarci That one goes to the market. (gismu selbri)

ta cu blari'o That is blue-green. (lujvo selbri)

ti cu djarspageti This is spaghetti. (fu'ivla selbri)

All three work exactly the same way in a sentence — the grammar does not care which subtype you use.

Particles (cmavo in Lojban)

Short structural words — the grammar glue of Lojban. They begin with a consonant followed by a vowel, optionally with more apostrophe-vowel sequences. Particles are often written together without spaces.

Examples: le (the), cu (selbri-separator), mi (I), pu (past tense)

Name words (cmevla in Lojban)

Names of people, places, etc. They always end in a consonant and are surrounded by pause marks (periods) when written.

Examples: .alis. (Alice), .teris. (Terry), .lojban. (Lojban)

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Place Structures#

Every relation word has a place structure — a list of numbered slots that define the roles of the participants. These slots are labeled x₁, x₂, x₃, and so on.

tavla

x₁ talks to x₂ about topic x₃ in language x₄

prami

x₁ loves x₂

klama

x₁ goes/comes to x₂ (destination) from x₃ (origin) via route x₄ by means x₅

citka

x₁ eats x₂

gerku

x₁ is a dog of breed x₂

The place structure is part of every word's definition. When you fill in the slots with arguments, you get a sentence.

Swapping Places: se, te, ve, xe#

Sometimes you want to put a different argument in the x₁ slot — for emphasis or because of what is already in context. The particles se, te, ve, xe swap x₁ with another place:

Using klama (x₁ goes to x₂ from x₃ via x₄ by x₅):

mi klama le zarci I go to the market. (x₁=I, x₂=market)

le zarci se klama mi The market is gone-to by me. (x₁=market, x₂=I — places swapped)

le zdani te klama mi le zarci The house is the origin: I go to the market from it. (x₁=house, x₂=I, x₃=market — wait, let's be precise: te swaps x₁↔x₃, so x₁=origin=house, x₂=mi, x₃=destination=zarci)

A shorter example with vecnu (x₁ sells x₂ to x₃ for x₄):

la .teris. vecnu le karce la .alis. Terry sells the car to Alice.

le karce se vecnu la .teris. la .alis. The car is sold by Terry to Alice. (x₁=car, x₂=Terry)

la .alis. te vecnu la .teris. le karce Alice is the buyer: Terry sells the car to her. (x₁=Alice, x₃ becomes x₁)

Conversions are the standard Lojban way to form passive-like constructions and are very common.

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The Simplest Sentences#

The basic word order is: x₁ selbri x₂ x₃ …

The first argument before the selbri fills x₁; arguments after the selbri fill x₂, x₃, in order.

mi prami do I love you.

mi

I, me (x₁ of prami)

prami

… loves …

do

you (x₂ of prami)

le tirxu cu klama le barda tcadu The tiger goes to the big city.

le tirxu

the tiger (x₁ of klama)

klama

… goes to …

le barda tcadu

the big city (x₂ of klama — destination)

mi tavla do I talk to you.

la .teris. cu citka Terry eats.

la .teris.

the one named Terry

When you leave a slot unfilled at the end of a sentence, it is treated as "unspecified" — the listener infers from context. So la .teris. cu citka just means Terry eats (something unspecified).

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The cu Separator#

The particle cu separates the last sumti before the selbri from the selbri itself. It has no meaning on its own — it just marks where the relation begins.

mi tavla do I talk to you. (cu optional here — no ambiguity)

le sutra prenu cu tavla The fast person talks.

sutra

… is fast

prenu

… is a person

Without cu in that last example, le sutra prenu tavla would be parsed as "the fast-person-type-of talker" — a description, not a sentence. The cu signals: "what follows is the relation, not more description".

The rule: cu is needed whenever a description sumti (le…) ends right before the selbri and the parser might otherwise absorb the selbri into the description.

In practice, beginners can start most sentences with mi or do or la .name. and omit cu freely — it only becomes essential in more complex sentences. You'll develop a feel for when it's needed.

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Basic Sumti: Pronouns#

A handful of particles work directly as sumti (arguments) without needing a relation word:

mi and do do not distinguish singular from plural or any gender — that information can be added later if needed, but is not required.

zo'e is Lojban's "placeholder" — it explicitly says "there is some value here but I'm not saying what it is". Trailing zo'e slots at the end of a sentence can simply be omitted.

More than one sumti before the selbri#

You can place more than one sumti before cu + selbri. The place numbers stay fixed — you are only choosing how many arguments sit in the “before the relation” zone, often for emphasis or style (the same bridi can be said several equivalent ways).

vecnu: x₁ is a seller, x₂ is goods sold, x₃ is a buyer, x₄ is a price.

mi cu vecnu ti ta zo'e I sell this to that (price left unspecified).

mi ti cu vecnu ta I — this — sell to that. (same claim: x₁ mi, x₂ ti, x₃ ta)

mi ti ta cu vecnu I — this — to that — sell. (same claim again)

The examples above cover the same sumti-order moves.

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Names as Sumti#

Personal names and proper nouns are preceded by la:

la .alis. cu tavla Alice talks.

la .teris. cu klama le barda tcadu Terry comes to the big city.

Names end in a consonant and are surrounded by pause marks. The pause before a name with la is usually written as the period that's part of the name itself.

coi .alis. Hello, Alice!

coi la .teris. Hello, Terry!

Names can be Lojbanized versions of names from any language. The Lojban name for a person named "John" might be .djan., for "Mary" .meris., and so on. The rules for forming valid Lojban names are in Chapter 14.

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The Observative#

If you start a sentence directly with the selbri — no x₁ before it — you get an observative: a quick announcement of something noticed.

klama Someone/something is going! (or: Coming!)

gerku Dog! (upon seeing one)

Observatives are the Lojban equivalent of English shouts like "Fire!" or "Car!" — they announce the relationship without specifying who is involved. They cannot use cu (there's nothing to separate).

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Sentence Separators#

Multiple sentences are linked by .i (a standalone particle):

mi prami do .i do prami mi I love you. You love me.

.i is like a period/full stop that is also spoken aloud. It prevents the beginning of the next sentence from being mistakenly parsed as a trailing argument of the previous one.

For paragraph breaks (a new topic), use ni'o:

ni'o la .teris. cu blabi tirxu [New topic:] Terry is a white tiger.

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Compound Relations: tanru#

When two relation words appear side by side as the selbri, the first modifies the second. The combination is called a tanru.

sutra tavla fast talker (x₁ is a fast type-of talker to x₂ about x₃ in language x₄)

barda tcadu big city

blabi gerku white dog

The place structure of a tanru is always that of the rightmost word. The modifying word adds a flavor of meaning — exactly what flavor is deliberately left vague and context-dependent, just as English compounds like "lemon tree" or "stone wall" are understood from context.

Three or more words chain the same way: each new word on the left modifies everything to its right:

sutra tavla gerku fast-talker type of dog (a dog in the way that a fast talker is)

Tanru are very common in Lojban and an expressive and creative tool. Their vagueness is intentional — when you need precision, you use other constructions (covered in Chapter 14).

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Descriptions: le … (ku)#

To refer to a specific person or thing, wrap a selbri (or tanru) in le … ku:

le gerku the dog (literally: "that which I describe as a dog")

le sutra tavla the fast talker

le barda tcadu the big city

The ku at the end is often omitted when the description comes at the end of a sentence or when the boundary is clear from context.

le is a descriptor — it says "I have a specific thing(s) in mind that I'm describing as …". The description is the speaker's framing, not necessarily a verified fact (the dog might be debatable, but the speaker is thinking of it that way).

You can use any relation or tanru after le:

le prami be mi the one who loves me (be attaches x₂ inside the description — covered in Chapter 11)

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Describing the Past and Future (Preview)#

Lojban bridi are tenseless by default — the time is inferred from context. But you can add a tense particle before the selbri:

mi pu klama le zarci I went to the store. (pu = past)

mi ca tavla do I am now talking to you. (ca = present/now)

mi ba klama I will go. (ba = future)

pu

(particle) past tense

ca

(particle) present / now

ba

(particle) future tense

Tense is always optional in Lojban — omitting it does not make the sentence ungrammatical, just temporally vague.

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A Starter Vocabulary#

Here are some useful relation words to get you started. Each entry shows the full place structure.

People & actions

prami

x₁ loves x₂

tavla

x₁ talks to x₂ about x₃ in language x₄

klama

x₁ goes to x₂ from x₃ via x₄ by means x₅

citka

x₁ eats x₂

sipna

x₁ sleeps/is asleep

cliva

x₁ leaves x₂

vecnu

x₁ sells x₂ to x₃ for price x₄

Properties

melbi

x₁ is beautiful/pretty to x₂ by standard x₃

barda

x₁ is big/large in dimension x₂ by standard x₃

cmalu

x₁ is small/little in dimension x₂ by standard x₃

sutra

x₁ is fast/quick at doing x₂

blari'o

x₁ is blue-green (cyan/teal) of shade x₂

pluka

x₁ is pleasant/pleasing to x₂ under conditions x₃

Things

zarci

x₁ is a market/store selling x₂ run by x₃

tcadu

x₁ is a city/town of x₂

gerku

x₁ is a dog of breed x₂

tirxu

x₁ is a tiger of species x₂

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A Short Dialogue#

Here is a short Lojban exchange using what you now know:

coi .alis. Hello, Alice.

coi .djan. .i do mo Hello, John. What's up? (mo = what relation? — a selbri question)

mi klama le zarci .i xu do klama I'm going to the store. Are you going? (xu = yes/no question marker)

je'u go'i Yes (literally: "truly [that]")

je'u

indeed, truly (an evidential attitudinal)

go'i

[repeat the previous bridi / yes]

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Terminology at a glance#

Quick definitions you will see in every chapter (full detail unfolds as you read):

For how sumti divide into description / pro-sumti / name / quotation / number, see Chapter 3.

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Summary#

• Terminology table: bridi, sumti, selbri, brivla, cmavo, cmevla, gadri — see Terminology at a glance above; five sumti kinds in Ch.3
• A Lojban sentence (bridi) = a selbri (relation) + sumti (arguments filling numbered slots x₁ x₂ …)
• Default word order: x₁ first, then selbri, then x₂ x₃ …
• More than one sumti may appear before cu + selbri (same places — style/emphasis) — see vecnu examples above
• cu separates a preceding description from the selbri when needed
• Pronouns: mi (I), do (you), ti/ta/tu (this/that)
• Names: la .name. — always end in a consonant, surrounded by pause marks
• Descriptions: le selbri — "the thing I describe as …"
• Tanru: two relation words side by side — first modifies second; place structure from rightmost
• Tense is optional: pu (past), ca (now), ba (future)
• Multiple sentences: separated by .i
• Brivla subtypes: gismu (root words), lujvo (compounds), fu'ivla (borrowings) — all grammatically identical
• Conversions se/te/ve/xe: swap x₁ with x₂/x₃/x₄/x₅ (Lojban's passive construction)

Chapter 3. Describing Things#

Two Ways to Say "The"#

In Chapter 2 you learned le as the basic way to refer to a specific thing. Lojban actually has two common descriptors, and understanding the difference between them is important:

le — "the one I describe as …"

Refers to something the speaker has specifically in mind. The description is the speaker's own framing and doesn't have to be objectively true. le is like English the — you use it when you and the listener both know (or can figure out) what you're talking about.

lo — "something that actually is a …"

Refers to one or more things that genuinely fit the description — things that would make a true bridi with that relation as selbri. lo is like English a/an or some — you use it for real instances without singling out which ones.

Compare:

le gerku cu melbi The dog is beautiful. (I have a specific dog in mind)

lo gerku cu melbi A dog is beautiful. / Some dog(s) are beautiful. (genuine dogs, which ones not specified)

le nanmu cu ninmu The man is a woman. (grammatically fine — maybe I was wrong about the gender; le only says I'm describing them as a man, not that they really are one)

lo nanmu cu ninmu Some man is a woman. (this would have to be factually true to assert)

The practical upshot: use le for things you're pointing at or have talked about before; use lo for things in general or when you're introducing something new without specifying which individual.

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The five kinds of simple sumti#

Reference grammars anchor vocabulary by sorting sumti (arguments) into a few simple shapes. Everything in this chapter is mostly about kind 1; the others are named here so you can place what you already know.

mi klama le zarci I go to the store. — mi (pro-sumti) + le zarci (description).

Complex sumti add relative clauses, sumti qualifiers (la'e, tu'a, …), abstractions, and more — they still sit in the same argument slots; the subsequent sections of Chapter 3, Chapter 11 (relative clauses), and Chapter 12 (abstractions) cover each type.

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Numbers Before Descriptions#

You can place a number directly before le or lo to say how many things you mean:

pa le gerku cu blabi One of the dogs is white.

re lo prenu cu klama Two people come.

ci le mlatu cu sipna Three of the cats are sleeping.

Basic numbers:

Numbers in Lojban must be exact. If you say re le gerku, you are claiming exactly two dogs, not "about two" or "at least two". To say "at least", use su'o:

mi ponse su'o re cutci I own at least two shoes.

To say "all", use ro:

ro le gerku cu blabi All of the dogs are white.

ro

all / every

su'o

at least one / some

These two — ro and su'o — are Lojban's fundamental quantifiers. More on quantification in Chapter 13.

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Inner Quantifiers: Saying How Many There Are#

A quantifier placed inside a description (between the descriptor and the relation word) declares the total number of things in the group — not how many you're talking about this time.

re le ci gerku cu blabi Two of the three dogs are white.

le ci gerku

the three dogs (inner quantifier ci: there are exactly three)

re le ci gerku

two of those three (outer quantifier re: we're asserting something about two of them)

In plain conversation, inner quantifiers are used mainly with le when you want to be precise about the size of the group you have in mind. Most of the time you can omit them and let context fill in.

Full inner/outer interaction rules:

The outer quantifier picks a subset of the group named by the inner quantifier:

su'o re le ci gerku cu blabi At least two of the three dogs are white.

The outer su'o re picks at least two members; the inner ci defines the total pool as three.

There is a subtle difference between le and lo inner quantifiers:

• For le, the inner quantifier reflects the speaker's framing — le ci nanmu means "what I describe as three men." It need not be objectively true. The speaker claims there are three.
• For lo, the inner quantifier is always veridical — lo ci gerku claims there genuinely are exactly three dogs in the domain.

Full default quantifier table for all 11 descriptors:

The pattern extends to the whole family of Lojban descriptors. Masses (lei/loi/lai) and sets (le'i/lo'i/la'i) use fractional quantifiers piro ("the whole of") and pisu'o ("some part of") because a mass or set is a single collective object — it doesn't make sense to count two distinct masses of the same members.

Why piro for sets, pisu'o for masses? A set is one object — you always refer to the whole set or a definite subset. A mass is also one collective object, but you typically act on some part of it (drinking from a glass of water, eating from a loaf of bread).

piro and pisu'o are fractional quantifiers: pi is the decimal point, so piro = "the entirety" and pisu'o = "at least some portion."

pisu'o loi djacu cu blanu Some of the water (mass) is blue.

piro le'i prenu cu nanmu The entire set of people (I have in mind) consists of men.

So le gerku = su'o le ro gerku = "at least one of all the dogs I have in mind."

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The Typical: lo'e and le'e#

Two special descriptors let you talk about a typical member of a category rather than a specific one.

lo'e — "the typical …" (objective typical)

Refers to an imaginary representative that best exemplifies what that kind of thing is really like.

lo'e cinfo cu xabju le fi'ortu'a The (typical) lion lives in Africa.

This says something true about lions as a kind — not that every individual lion lives in Africa, but that it's characteristic. You're describing the idealized lion, not any particular one.

le'e — "the stereotypical …" (subjective typical)

Like lo'e but based on the speaker's mental image, which may be culturally specific or even a stereotype.

le'e mlatu cu nelci le finpe The stereotypical cat likes fish.

lo'e and le'e are useful for making generic statements — "dogs are loyal", "students are busy" — without committing to claims about every individual.

lo'e vs le'e — the key distinction:

• lo'e gerku = the objectively typical dog — the ideal representative as defined by the biology and nature of dogs.
• le'e gerku = the stereotypical dog as the speaker (or community) conceives it — which may reflect cultural assumptions rather than objective fact.

lo'e gerku cu batci Dogs (typically/objectively) bite. — true of dogs as a species

le'e gerku cu pendo Stereotypically, dogs are friendly. — a common belief, but not universally true

Neither lo'e nor le'e refers to any specific individual. Their implicit count is effectively pa (one ideal/stereotype). You cannot meaningfully say "two typical dogs" — there is only one ideal.

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Tanru Grouping with bo#

In Chapter 2 you learned that putting two relation words side by side creates a tanru where the first modifies the second. When you add a third word, Lojban's default is left-grouping: the leftmost two bind first.

cmalu nixli ckule = (cmalu nixli) ckule — "a (small girl)-type school" = a school for small girls

To group differently, use bo to bind the two words to its right most tightly:

cmalu nixli bo ckule = cmalu (nixli ckule) — "a small (girl-school)" = a small school for girls

bo always signals: "bind me to what comes directly after me".

Compare:

la .teris. cu barda melbi tirxu Terry is a (big-beautiful)-type tiger. (big beauty modifies tiger)

la .teris. cu barda melbi bo tirxu Terry is a big (beautiful-tiger). (beautiful tiger modifies the whole; Terry is a big beautiful-tiger)

A useful way to think about it: without bo, groups build from left; with bo, the bo-pair is the tightest bond.

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Grouping with ke … ke'e#

For longer or more complex tanru, ke and ke'e work like parentheses: everything between ke and ke'e is treated as a single tanru component.

ta ke melbi cmalu ke'e nixli ckule That is a ((beautiful small) girl) school. = a school for beautifully small girls

ta melbi ke cmalu nixli ke'e ckule That is a (beautiful) (small girl) school. = a beautifully-small girls' school

ke'e can be omitted at the end of the selbri if there's no ambiguity:

ta melbi ke cmalu nixli ckule (same meaning, ke'e dropped at end)

As a beginner you can get by with bo for most grouping needs. ke…ke'e is for when you need precise three-way or four-way distinctions.

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Masses: lei and loi#

So far, le and lo treat their referents as individuals — even if there are multiple, each one individually satisfies the bridi.

le prenu cu bevri le pipno The person(s) carry the piano. — each person, individually, carries it

But sometimes things only work together. Two people might together carry a piano, even though neither could alone. For this, Lojban has mass descriptors:

lei — "the mass of those I describe as …"

Like le but treats the group as a single collective unit.

lei prenu cu bevri le pipno The people (as a group) carry the piano. — they carry it together

loi — "some of the mass of those that really are …"

Like lo but mass.

loi cinfo cu xabju le fi'ortu'a Lions (as a kind) live in Africa. (some part of the mass of all lions)

Masses inherit the properties of their members. A mass of people carrying a piano collectively is doing what individuals together accomplish. A mass of tall and short people can be both tall and short — which is why mass reasoning isn't ordinary logic.

For most everyday sentences you'll use le and lo. Masses become important when talking about collective actions or generic truths about a kind.

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Sets: le'i and lo'i#

Sets are the third kind: a collection considered as a mathematical object.

le'i — "the set of those I describe as …"

lo'i — "the set of those that really are …"

lo'i gerku cu barda The set of all dogs is large. (it has many members)

Sets have properties like size and membership, but don't inherit the properties of their members. The set of dogs is not brown, even though some dogs are. Sets are used mainly with predicates that explicitly require a set in their place structure — most everyday talk uses le and lo instead.

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A Vocabulary Snapshot: Common Properties#

Here are some useful property words (relation words whose x₁ is the thing having that property):

blabi

x₁ is white

xekri

x₁ is black

pelxu

x₁ is yellow

crino

x₁ is green

blanu

x₁ is blue

xunre

x₁ is red

barda

x₁ is big/large

cmalu

x₁ is small/little

clani

x₁ is long/tall

tordu

x₁ is short

melbi

x₁ is beautiful/attractive to x₂ by standard x₃

pluka

x₁ is pleasing/pleasant to x₂ under conditions x₃

xlali

x₁ is bad/undesirable by standard x₂

Any of these can form a tanru with a noun-like relation word:

le blabi mlatu the white cat

lo barda tcadu a big city

le melbi nixli the beautiful girl

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Examples from Real Lojban#

le pa tirxu be me'e zo .teris. pu ki kansa le za'u pendo The one tiger named Terry used to live together with the many friends.

(From Terry the Tiger Visits the Big City — showing le pa tirxu with inner quantifier pa and name label me'e zo .teris.)

la .teris. co'a cadzu klama le bi'unai barda tcadu Terry started walking to the (already-mentioned) big city.

(The tanru barda tcadu = "big city" is used naturally throughout the story.)

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Sumti Qualifiers: Shifting What a Sumti Means#

Sometimes you want to talk about something associated with a sumti rather than the sumti itself. Lojban provides sumti qualifiers that wrap around any sumti and shift its reference:

la'e — "the referent of"

Takes a description or name and refers to what it points to, not the description itself.

la'e di'u cu jitfa The referent of the previous sentence is false. → What was described is false.

lu'e — "a symbol/name for"

The reverse of la'e — takes something and refers to a symbol for it.

lu'e la .djan. cu se cusku mi I said a name for John. (= I said "John" or something referring to him)

tu'a — "something associated with" (vague)

A loose sumti-raiser — refers to some event or fact related to the sumti.

mi djica tu'a le plise I want something about/involving the apple. (want to eat it? own it? — vague)

tu'a is a shorthand for "some event or property related to [X]". It's common when the full abstraction would be tedious:

mi djica tu'a do = I want something from you / I want you to do something.

When you need to be precise, replace tu'a with an explicit abstraction (le nu …, le du'u …, le ka …) that names the event or claim you mean.

The most practical qualifier is la'e:

mi nelci la'e le cukta I like what the book is about. (not just the physical book)

mi ctuca la'e le cusku be do I teach what you said. (the content, not the utterance)

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Indefinite Descriptions and zo'e#

Lojban's most "implicit" sumti are the indefinite ones — sumti that exist but don't need to be named:

zo'e — "something real but unspecified"

Explicitly fills a slot with an unspecified value. Trailing zo'e slots can be omitted; inner slots need the word.

mi klama le zarci zo'e le karce I go to the store via [unspecified] by car.

zi'o — "doesn't exist / this place doesn't apply"

Eliminates a place entirely from the predicate. The resulting predicate doesn't have that slot.

mi dunda le cukta zi'o I give the book. (no recipient — zi'o removes x₃ rather than leaving it vague)

Compare:

mi dunda le cukta zo'e — I give the book to someone (unknown) mi dunda le cukta zi'o — I give the book (giving without a recipient is meaningful)

su'o — "at least one" as descriptor

su'o le gerku = "at least one of the dogs" — more explicit than a plain lo gerku.

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Indefinite Descriptions: Bare Number Without lo#

When you write an explicit outer quantifier without any descriptor, Lojban allows you to drop lo:

re gerku cu batci mi Two dogs bite me. (= re lo gerku cu batci mi)

This only works when there is no inner quantifier — just a plain number followed directly by the brivla. The meaning is always lo-like (genuine instances, veridical). This shorthand is common in spoken Lojban. You cannot drop le this way — bare numbers always imply lo.

ci prenu cu klama = Three people come. (at least three genuine people)

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Sumti-based Descriptions#

A sumti-based description is one where a sumti appears in the slot normally filled by a selbri. The inner quantifier is required and must be explicit.

The most common case: describe a subset of a group you are already talking to or about.

re do cu nanmu Two of you are men. (of the listeners, size unknown, two are men)

le re do cu nanmu The two of you are men. (I have a group of two listeners specifically in mind; all of them are men)

In le re do, the inner quantifier re gives the size of the group the inner sumti do refers to. The implicit outer ro then says "all of those two."

Nesting is possible:

re le ci cribe cu bunre Two of the three bears are brown.

le re le ci cribe cu bunre The two-of-the-three bears are brown. (a specific pair from that group of three)

pa le re le ci cribe cu bunre One of the two-of-the-three bears is brown. (one specific bear from a specific pair from the original three)

Each layer of le + inner quantifier narrows the group further. This construction is rarely needed in everyday speech, but appears in formal or careful writing when precise reference is required.

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Possessive Sumti as Internal pe Relative Phrase This is actually a hidden pe relative phrase:#

le mi karce = le karce pe mi = the car associated with me

Any sumti placed between a descriptor and its selbri works exactly like a pe-phrase. All the scoping and attachment rules for pe apply. This means:

le do ckule = le ckule pe do = your school

le pa nanmu nixli = le nixli pe le pa nanmu = the girl of the one man

The possessive-as-internal construction is purely a notational convenience. For precise relative clauses or complex possession, use explicit pe/po/po'e/po'u.

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la + selbri: Names from Relation Words#

la can be followed not just by a proper name but by any selbri:

la gerku = "the one(s) called 'gerku'" / "the one(s) named Dog"

This refers to something that has been given the name gerku, not to an actual dog. It is quite different from lo gerku (genuine dogs) or le gerku (things I describe as dogs):

The implicit outer quantifier for la + selbri is su'o (at least one), just like la + proper name. This usage is common for giving descriptive nicknames or referring to characters in stories by their role names.

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Quotations and numbers (full chapters)#

Simple-sumti kinds 4 (quotations) and 5 (li / mekso) are only named early in this chapter; the teaching lives where they are used most:

• Quotations — lu … li'u, zo, zoi, lo'u … le'u, la'o, …: Chapter 17 — Text Structure & Quotation.
• Numbers and mathematical expressions — PA, li, operators: Chapter 18 — Letters, Numbers & Math.

Names and pro-sumti are in Chapter 5; descriptions are the bulk of this chapter. Together these replace CLL’s single end-of-chapter “quotation / number” boxes — same content, friendlier pacing.

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Summary#

• Five kinds of simple sumti: descriptions (le/…), pro-sumti, names, quotations, li-numbers — see table at the start of this chapter
• Quotations & numbers: full lessons in Ch.17 and Ch.18 (see Quotations and numbers above)
• le = "the … I have in mind" (specific, speaker's framing)
• lo = "some actual …" (genuine instances, non-specific)
• Number before descriptor = outer quantifier (how many we're talking about)
• Number inside descriptor = inner quantifier (how many there are total)
• ro = all; su'o = at least one
• lo'e = the typical …; le'e = the stereotypical …
• Tanru grouping: default is left; bo tightens its right neighbor; ke … ke'e are parentheses
• lei/loi = mass descriptors (collective); le'i/lo'i = set descriptors (mathematical)
• la'e = the referent of (shifts from symbol to thing)
• lu'e = a symbol for (shifts from thing to symbol)
• tu'a = something related to (vague sumti-raiser; paraphrase with nu/du'u/ka when precision matters)
• zi'o = this place doesn't apply (removes a slot)
• Bare number without descriptor (e.g. re gerku) = shorthand for re lo gerku (veridical, no le equivalent)
• le mi karce = le karce pe mi — internal sumti between descriptor and selbri is a hidden pe phrase
• lo'e = objective typical (nature); le'e = subjective stereotypical (speaker's image); both count as pa (one ideal)
• la gerku = the one(s) named gerku — distinct from lo gerku (actual dogs)
• Inner quantifier of le reflects speaker's framing (need not be true); inner quantifier of lo is veridical
• Full default quantifier table covers all 11 descriptors; masses use pisu'o, sets use piro
• Sumti-based descriptions (le re do, le re le ci cribe): sumti fills the selbri slot; inner quantifier required

Chapter 4. Rearranging & Tagging Places#

Motivation#

In the default Lojban word order, x₁ comes before the selbri and the rest follow in numbered order. This works perfectly for simple sentences. But what if you want to:

• Omit a middle place while filling a later one?
• Put Boston first in the sentence for emphasis?
• Make it crystal clear which slot a long, complex argument fills?

Lojban has two tools for this: FA place tags and SE conversion.

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FA Place Tags#

The five particles fa fe fi fo fu explicitly label which place a following sumti fills.

Place any of these immediately before a sumti to declare its slot, regardless of position in the sentence.

mi cu klama la bastn. la .atlantas. zo'e le karce I go to Boston from Atlanta via (unspecified) by car.

Using FA tags, this can be rewritten with any order:

fu le karce fo zo'e fi la .atlantas. fe la bastn. fa mi klama x₅=the car x₄=unspecified x₃=Atlanta x₂=Boston x₁=I — go

Both sentences mean the same thing.

FA tags shine when you need to skip a middle place without using zo'e:

mi klama la bastn. la .atlantas. zo'e le karce I go to Boston from Atlanta via (?) by car. — zo'e fills x₄

mi klama fe la bastn. fi la .atlantas. fu le karce I go x₂=Boston x₃=Atlanta x₅=car — x₄ (route) is simply absent

klama fi la .atlantas. fe la bastn. A-goer x₃=Atlanta x₂=Boston — x₁ empty (observative style), x₂ and x₃ in reverse order

After a tagged sumti, any subsequent untagged sumti fill the slots that immediately follow the tagged one in numerical order (skipping already-filled slots). So you can tag just one problematic sumti and let the rest flow naturally:

mi klama fi la .atlantas. la bastn. le dargu le karce — fa=mi (x₁, before selbri), fi=la .atlantas. (x₃), then la bastn. fills x₂? No —

Actually: after the fi tag, untagged sumti fill x₄, x₅ in order (skipping x₂ and x₃ already handled). So:

mi klama la bastn. fi la .atlantas. I go to-Boston x₃=from-Atlanta

Here x₁=mi, x₂=la bastn. (naturally second after selbri), x₃=la .atlantas. (tagged), x₄ and x₅ empty.

fi'a: The Place-Structure Question#

fi'a is a special FA particle that asks which place a sumti occupies:

fi'a do dunda le vi rozgu In what role are you involved in the giving of this rose?

The listener can reply with a bare FA particle: fa (you are the giver) or fi (you are the recipient).

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SE Conversion#

FA tags move arguments around. SE conversion goes deeper: it actually restructures the selbri itself, swapping x₁ with another place to produce a new relation word with a new place structure.

The result is a new selbri that is placed before the original verb. The new x₁ is whatever was x₂ (or x₃, etc.) of the original.

klama place structure: x₁ goes to x₂ from x₃ via x₄ by x₅

se klama place structure (x₁ ↔ x₂): x₁ is the destination; x₂ is the traveler; x₃=origin, x₄=route, x₅=means

la bastn. cu se klama mi Boston is gone-to by me. (Boston is the destination of my going)

This is the Lojban equivalent of the passive voice. It says the same underlying fact as mi klama la bastn. but promotes Boston to x₁.

te klama (x₁ ↔ x₃): x₁ is the origin; x₂ is the destination; x₃ is the traveler

la .atlantas. cu te klama mi la bastn. Atlanta is the origin of my going to Boston.

ve klama (x₁ ↔ x₄): x₁ is the route; x₂=destination, x₃=origin, x₄=traveler

le dargu cu ve klama mi la bastn. The road is the route of my going to Boston.

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SE in Descriptions#

SE conversion becomes especially useful when building descriptions with le. Recall that le selbri takes the x₁ of the selbri as the thing described:

le klama — the goer (x₁ of klama = the traveler)

le se klama — the destination (x₁ of se klama = the place gone to)

le te klama — the origin (x₁ of te klama = the place gone from)

le ve klama — the route (x₁ of ve klama = the path taken)

le xe klama — the means (x₁ of xe klama = the vehicle/method)

This is powerful: from a single five-place relation, you get five description types — traveler, destination, origin, route, means — by just prefixing the right SE.

More examples with dunda (x₁ gives x₂ to x₃):

le dunda — the giver

le se dunda — the gift (x₂ of dunda)

le te dunda — the recipient (x₃ of dunda)

And with tavla (x₁ talks to x₂ about x₃ in language x₄):

le se tavla — the listener / audience

le te tavla — the topic of discussion

le ve tavla — the language used

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Multiple SE#

You can stack two SE particles, but they are evaluated left to right:

se te klama

First apply se (swap x₁↔x₂): x₁=destination, x₂=traveler, x₃=origin Then apply te (swap x₁↔x₃ of the already-converted result): x₁=origin, x₃=destination

In practice, stacked SE is rarely used because FA tags or a single well-chosen SE usually suffice.

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jai: Converting a Modal Tag into x₁#

jai followed by a modal tag (BAI or fi'o phrase) converts the selbri so that the modal argument becomes x₁ of the new selbri. The original x₁ is demoted to the special place fai:

le vorme jai co'a kalri The door [x₁ = door] begins-to-open. (intransitive; door is the mover)

mi jai gau klama I am the agent of going. (= I cause going to happen; gau fills x₁ with the agent)

The structure: jai gau klama means "is an agent of going" — x₁ of the converted selbri is the agent (gau = gasnu = agent). The original x₁ of klama (the goer) moves to fai if needed:

mi jai gau klama fai le bende I cause the team to go. (mi = agent in x₁; le bende = original x₁ of klama, now in fai)

jai with any modal tag:

SE conversion of jai-selbri is also valid:

le bende cu se jai gau klama mi The team is caused-to-go by me. (se moves the fai argument back to x₁)

This is how Lojban handles causative alternations cleanly without changing the base selbri.

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Word Order and Emphasis#

Both FA tags and SE conversion change which argument is in the x₁ slot — the grammatical "topic" position. In Lojban, information moved out of its default position carries extra emphasis.

Standard order (neutral):

mi tavla do I talk to you.

Emphasizing the listener (fe brings x₂ forward, or se promotes it):

do cu se tavla mi You are talked-to by me. (emphasis: you are the one being talked to)

Emphasizing the selbri (observative, no x₁):

tavla mi do There's talking going on — I'm talking to you!

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zo'e: The Explicit Placeholder#

When you need to skip a middle place without tagging, use zo'e ("the unspecified/obvious thing"):

mi klama la bastn. la .atlantas. zo'e le karce I go to Boston from Atlanta via (unspecified route) by car.

zo'e doesn't claim there is no value — it says the value is real but either obvious from context or not relevant to state. You can use zo'e in any place, in any position.

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Summary#

• fa fe fi fo fu tag sumti to specific places x₁–x₅, freeing word order
• After a tagged sumti, untagged sumti fill the next numerically available places
• fi'a asks "which place?"; answered with a bare FA particle
• se te ve xe convert the selbri by swapping x₁ with x₂/x₃/x₄/x₅
• SE gives new selbri: le se klama = the destination, le te klama = the origin, etc.
• zo'e explicitly fills a place with an unspecified value
• Moving arguments out of default position adds emphasis

Chapter 5. Pronouns & Back-References#

Why Lojban Needs Its Own Pronoun System#

English pronouns like he, she, it, they carry implicit information about gender and number. Lojban does not use grammatical gender at all, and number is optional — so the English pronoun system doesn't map cleanly onto Lojban. Instead, Lojban has several series of pro-sumti, each organized around a specific function.

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The mi-series: Personal Pronouns#

The most fundamental pronouns refer to the participants in the conversation.

Neither mi nor do specifies singular or plural. A spokesperson saying "we believe …" would use mi on behalf of a group.

The "we" pronoun series is more precise than English: Lojban distinguishes whether the listener is included (mi'o = you and I; mi'a = we without you). This eliminates a common ambiguity in English: "We're going to the store" — does that include you?

ko is the command particle. It can go in any sumti slot:

ko klama le zarci Go to the store! (literally: make "you go to the store" true)

mi viska ko Make "I see you" true! = Be seen by me! / Show yourself!

ko kurji ko Take care of yourself! (ko in both x₁ and x₂)

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The ti-series: Demonstrative Pronouns#

Three pronouns refer to things pointed at in physical space:

ti

this — something near the speaker

ta

that — something at a medium distance (often near the listener)

tu

that yonder — something far from both speaker and listener

ti melbi This is beautiful.

mi klama tu I'm going to that (far-away thing).

Note: ti, ta, tu are true pronouns — they replace the whole argument. To say "this boat" (the boat near me), use a tense tag, not ti:

le vi bloti — the nearby boat (vi = "here")

ti noi bloti — this thing, which happens to be a boat

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The di'u-series: Utterance Pronouns#

Sometimes you want to refer to something that was said rather than something physical. The di'u-series refers to utterances — sentences, sentences, passages of text:

do na nelci loi mlatu .i di'u jitfa You don't like cats. That [previous utterance] is false.

di'u refers to the sentence as a piece of text. If you want to refer to the situation described (not the words themselves), use la'e di'u ("the referent of the previous utterance"):

mi prami la .djan. .i mi nelci la'e di'u I love John. And I like that [= the situation of my loving John].

Contrast with:

mi prami la .djan. .i mi nelci di'u I love John. And I like [the sentence "I love John"]. — liking the sentence, not the fact

la'edi'u is often written as a single word. It's very common in Lojban text.

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The ko'a-series: Assignable Pronouns#

Lojban's equivalents of he/she/it/they are the ko'a-series — ten generic pronouns with no inherent reference. You assign them explicitly with goi.

Assigning with goi — forethought form:

la .alis. goi ko'a cu klama le zarci .i ko'a cu blanu Alice (hereafter: ko'a) goes to the store. She is blue.

Assigning with goi — afterthought form:

la .alis. klama le zarci goi ko'a .i ko'a blanu Alice goes to the store (call her ko'a). ko'a is blue.

Both la .alis. goi ko'a and ko'a goi la .alis. work identically — goi is symmetric.

Unlike English pronouns, ko'a-series pronouns carry no gender, no animacy, and no number — they refer to whatever you assigned them to. You can assign them to people, objects, places, or even abstract things like events.

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The ri-series: Relative Back-References#

Sometimes you want to say "the aforementioned …" without choosing a ko'a slot. The ri-series points back to recently mentioned sumti:

ri

the previous sumti (the most recently completed argument)

ra

an earlier sumti (vague — not the one ri refers to)

ru

a much earlier sumti (earlier than ra's referent)

la .teris. cu klama le zarci .i ri blanu Terry goes to the store. It [= the store, the most recent sumti] is blue.

Be careful: ri refers to the previous sumti in the text, not necessarily the subject. In the example above, ri is the store (last completed sumti) not Terry. If you want Terry:

la .teris. cu klama le zarci .i la .teris. cu blanu

or assign:

la .teris. goi ko'a cu klama le zarci .i ko'a blanu

ri is convenient for quick back-references; ko'a is for careful, unambiguous longer-range references.

Scan (parallel to the ti-series for distance): ri / ra / ru repeat sumti by recency; go'i / go'a / go'u repeat whole main-bridi patterns the same way (see The go'i-series later in this chapter).

ri before the surrounding sumti is finished: ri always copies the last complete sumti before it — not a phrase that is still open. A useful pattern is “in someone's room”:

la .teris. cu sipna ne'i le ri kumfa Terry sleeps in Terry's room. Here ri = la .teris. (the possessor), because le ri kumfa is not yet complete when ri appears.

The same meaning, spelled out without ri:

la .teris. cu sipna ne'i le la .teris. kumfa

So ri cannot refer to le ri kumfa itself — that would create a self-referential tangle. Inner sumti (here la .teris. inside the larger description) count as more recent than the outer phrase they sit in.

Why you still say the second mi: ri mostly skips mi, do, assignable ko'a…, zo'e, and ri itself. To say “I love myself”, repeat mi — ri will not stand in for the second slot:

mi prami mi I love myself.

For “x₁ of this bridi” in a specific place, vo'a is often clearer; see the section vo'a: The Reflexive below. This pair just shows why ri is not a substitute for another mi.

ti and ri: You may use ri after ti / ta / tu if you have just pointed at something new. Two ri in a row with nothing between them still pick the same antecedent:

la .teris. cu viska le tricu .i ri melbi Terry sees the tree. It [= the tree] is beautiful.

la .teris. cu viska le tricu .i ri du ri Terry sees the tree. It is the same as itself. (Both ri = le tricu — a deliberate “chain” of ri.)

Quotations: ri inside lu … li'u normally does not reach out to sumti in the surrounding narrative; see Chapter 17 for quotation rules and nearby-quote exceptions.

What ri counts and skips:

• ri counts every completed sumti in order of appearance — including ti/ta/tu (demonstratives), since you may have changed what you are pointing at.
• ri skips most KOhA cmavo: mi, do, ko'a-series, ko-imperatives, zo'e, and the ri/ra/ru words themselves.
• A sumti nested inside another sumti (e.g. inside a le description) counts based on its start position, not its container. So inner sumti are "more recent" than the container that wraps them.

Subscripted ri for exact targeting: When you need to skip back further than one sumti, use xi + a number:

lo smuci .i lo forca .i la rik. pilno ri xi re A spoon. A fork. Rick uses [the second-back = the fork].

ri xi re skips one and picks up the next-to-last sumti; ri xi mu skips four and picks up the fifth-from-last. In practice this is cumbersome in speech — prefer assigning a ko'a slot for anything beyond a one-step back-reference. Older texts sometimes write rixire glued together; it is the same as ri xi re.

When subscripts are awkward, use ra: The same scene, but with a vague “some earlier thing” instead of counting:

lo smuci .i lo forca .i la rik. pilno ra A spoon. A fork. Rick uses [some previous sumti — not la rik.].

Here ra usually means lo forca (the fork): the listener uses context. If even ra / ru feel fuzzy, assign once: le forca goi ko'e .i la rik. cu pilno ko'e.

Ordering rules for ra and ru:

• ra refers to a recently used sumti that is not the one ri would pick. If ri has not been used, ra may be the last sumti.
• ru refers to a sumti further back than ra's referent. If both ri and ra are used, ru must be even older.
• A chain of consecutive ri (no other sumti between them) all refer to the same sumti — each ri takes the previous ri's referent as its antecedent, which is the same underlying sumti.

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vo'a: The Reflexive#

To say the same thing fills two slots of the same bridi (like English "herself", "himself"):

vo'a

the same as x₁ of this bridi

vo'e

the same as x₂

vo'i

x₃; vo'o = x₄; vo'u = x₅

la .alis. cu prami vo'a Alice loves herself.

mi tavla do fo vo'a I talk to you in (my own) language. (vo'a = x₁ = mi)

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zo'e: The Unspecified#

zo'e is not exactly a pronoun but is worth reviewing here: it fills a place with "something real but unspecified":

mi citka zo'e I eat something (unspecified).

Trailing zo'e slots at the end of a bridi can simply be omitted:

mi citka = mi citka zo'e (eating something unspecified)

But when you need to skip a middle place while filling a later one, zo'e makes the skip explicit:

mi klama la bastn. la .atlantas. zo'e le karce I go to Boston from Atlanta via (unspecified route) by car.

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Names and Vocatives#

Names in Lojban always end in a consonant and are surrounded by pause marks. They come after la when used as sumti:

la .alis. cu tavla la .djan. Alice talks to John.

To address someone directly (a vocative), use a greeting particle followed by the name:

coi

hello / greetings

co'o

goodbye

doi

O [address marker, no greeting implied]

coi .alis. Hello, Alice.

co'o .djan. Goodbye, John.

doi .teris. ko klama Hey Terry, come here!

doi sets the value of do for the rest of the conversation:

doi la .alis. mi prami do [Addressing Alice:] I love you.

After doi la .alis., do refers to Alice until changed.

mi'e is the self-introduction vocative:

mi'e .djan. I am John.

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Pro-bridi: The broda-series and go'i#

Just as ko'a-series pronouns replace sumti, Lojban has pro-bridi that replace entire predicates or bridi.

The broda-series (broda, brode, brodi, brodo, brodu) are placeholder relation words, assigned with cei:

la .alis. cu gerku cei broda .i la .djan. broda Alice is a dog (call that "broda"). John is-broda. = John is also a dog.

go'i is the most commonly used pro-bridi: it repeats the previous main bridi, optionally with new sumti overriding the old ones:

mi klama le zarci .i do go'i I go to the store. You [go to the store too].

xu do klama le zarci .i go'i Are you going to the store? — Yes. (go'i alone = "the previous bridi is true")

na go'i No. / That is not so. (negated go'i)

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ce'u: The Abstraction-Focus Pronoun#

When you build a ka property abstraction (from Chapter 12), you sometimes need to indicate which open slot the property is "about". ce'u is that marker — the lambda variable of Lojban:

le ka melbi — the property of being beautiful (ce'u is implicit in x₁)

le ka ce'u melbi — the property [of x] of being beautiful (same, but explicit)

le ka mi prami ce'u — the property of being-loved-by-me (ce'u fills x₂)

Without ce'u, x₁ of the abstraction is assumed to be the open slot. With ce'u explicitly placed, you can build properties for any slot:

do cnino mi le ka ce'u melbi — You are new to me in the quality of being beautiful.

ta mutce le ka ce'u barda — That is very big. (literally: that greatly has the property of bigness)

ce'u is used with gismu like ckaji (has property), simlu (seems), mutce (very), traji (superlative), and wherever a ka abstraction needs to specify its open place.

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The go'i-series: Pro-bridi for Repeating and Referring#

go'i (covered briefly in the pronoun chapter) is one member of a larger family of pro-bridi — particles that substitute for whole predicates. The full series:

All of these can take new sumti to override specific places of the referred bridi:

mi klama le zarci .i do go'i I go to the store. You do too. (go'i = "go to the store", x₁ changed to do)

mi klama le zarci .i do go'i le zdani I go to the store. You go to the home. (go'i with x₂ overridden)

nei — this very bridi — is the opposite move from go'i: go'i replays the previous sentence; nei refers to the current predicate relationship while you are still inside it. That is what makes it useful for recursion and reflexive wording: you can nest the ongoing bridi inside itself (often as le nei “the/event of this bridi”) without naming the predicate again.

ra mipri le nei They hide themselves. (le nei packages this bridi as a sumti so the patient of mipri is tied back into the same clause — a natural reflexive).

Longer prose often uses le nu le nei … (an abstraction whose inner text still means “this bridi”), which is how translators handle English reflexives and self-referential descriptions in one smooth Lojban clause.

go'o — a later bridi (forward reference). Rare in textbook prose; one pattern is promising something that will be said next:

mi nupre le nu mi go'o I promise the event of my doing [what I will say next].

co'e (selma'o GOhA) is the pro-bridi for unknown/unspecified predicate — like zo'e but for selbri:

mi co'e le zarci I do [something unspecified] to the store.

le go'i — descriptions from a previous bridi's places:

Any GOhA word can be wrapped in le (or another descriptor) to extract a specific place of the repeated bridi as a sumti:

le xekri mlatu cu klama le zarci .i le go'i cu melbi The black cat goes to the store. The [same thing = the black cat] is beautiful.

le xekri mlatu cu klama le zarci .i le se go'i cu barda The black cat goes to the store. The [x₂ = the store] is large.

This lets you refer back to specific arguments of a previous sentence without repeating them or assigning ko'a slots.

go'e — the bridi before last:

go'e (= go'i xi re) is especially useful in conversation where two speakers alternate:

A: mi ba klama le zarci A: I will go to the store. B: mi nelci le si'o mi go'e B: I like the idea of my going [to the store — repeating A's bridi]. A: do go'i A: You will [go to the store] too.

Here B's go'e repeats A's sentence; A's final go'i repeats B's sentence. Tense particles are carried along automatically.

ra'o — updating pro-cmavo in reported speech:

When you quote or repeat someone else's words, the assignments they made (ko'a = X, broda = Y) were made in their context. ra'o tells a GOhA to re-evaluate pronoun assignments for the current speaker's context instead of copying them verbatim:

la alis. cusku lu mi prami ko'a li'u Alice says "I love [ko'a]." ra'o [Re-evaluate: for the listener, "mi" = Alice, "ko'a" = whatever Alice assigned it to.]

Without ra'o, go'i after reported speech would re-assert literally with the original speaker's referents. ra'o triggers context-shift so the repeated bridi makes sense from the new speaker's vantage point.

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da, de, di — bound sumti variables (logic)#

da, de, and di are the first three bound sumti slots — “thing-1”, “thing-2”, “thing-3”. They are meant for general statements (existence, “for all”, “if…then”) with quantifiers and often a prenex zo'u. Storytelling usually prefers names or ko'a; you reach for da when the point is logical form, not a specific individual you are tracking.

A minimal taste (details, scope, and negation live in Chapter 21):

da zo'u da klama Something goes. (existential reading: there is something that goes.)

su'o da poi gerku zo'u da blabi Some dog is white.

su'o da su'o de zo'u da prami de Something loves something. (two existentials in the prenex.)

If you see da in older text without an obvious quantifier, it often abbreviates su'o da (“at least one thing”). Don't confuse da with ko'a: ko'a is your label for a definite referent; da is a pattern variable under quantifiers.

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du — identity (“is the same as”)#

du is a selbri meaning identity: the sumti it connects are the same entity. It is the everyday “X is Y” when you identify or define, not merely compare.

ko'a du le nanmu ko'a is the man — you are saying what ko'a is (answering “what is ko'a?”).

la .alis. du le ninmu Alice is the woman — one person, two descriptions.

By contrast, mintu and similar selbri make a claim about similarity or sameness-of-kind between things you already have in mind — not the same speech act as a bare identity definition. (du is related historically to dunli, but dunli has extra places for how they are equal; du does not.)

du also appears as mathematical equals in Chapter 18 (li … du li …). The same “same value / same thing” idea, in number land.

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da'o — cancel assignable references#

da'o (selma'o DAhO) clears assignable back-references: ko'a–ko'u, fo'a–fo'u, broda–brodu after cei, and similar — so none of them inherit an old referent. It does not change who mi and do are (speaker and listener); it does not erase ri's discourse rules (there is nothing to “store” for ri anyway).

Use da'o when:

• you join a conversation and want to signal “don't assume my ko'a is yours”;
• a long stretch used many assignments and you want a clean slate before a new block;
• you are switching exercises or examples in a textbook.

Topic markers ni'o / no'i can also reset discourse context (see Chapter 17); heavy ni'o sometimes appears together with da'o at a major section break.

la .alis. goi ko'a cu gerku .i ko'a cu melbi Alice, called ko'a, is a dog. It is beautiful.

da'o .i ni'o la .djan. cu klama le zarci [Drop assignable pronouns.] [New topic:] John goes to the store.

After da'o, ko'a has no value until you assign it again with goi or cei.

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Lujvo from pro-sumti rafsi (advanced)#

Some cmavo in KOhA and GOhA have rafsi (combining forms) for building lujvo. This is specialist material — you can read Lojban fluently without ever using it — but it explains odd dictionary entries.

• Idea: attach a pro-sumti rafsi inside a lujvo as if it were an internal argument of the underlying predicate. Example from the reference grammar: donma'o (“you-cmavo”) ≈ second-person pronoun — glossed as cmavo be zo do (a cmavo for “you”). See the Lujvo from pro-sumti rafsi section in this chapter above.
• zi'o and other “place tricks” in lujvo use zi'o-rafsi patterns; the full convention is in Chapter 12 (abstractions) and Chapter 14 (how lujvo are formed and scored).
• co'e, du, and bu'a also have rafsi; compounds built from them pick up context-dependent meanings, like any vague tanru.

For the cmavo-to-rafsi table, Chapter 14 lists morphology details; jbovlaste lists rafsi when you need to check a coinage.

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bu'a: Selbri Variables#

bu'a, bu'e, and bu'i parallel da, de, di, but they stand in for selbri (relations), not sumti:

da bu'a de — something stands in some relation to something else

da bu'a de .ije de bu'a da — if A relates-to B then B relates-to A (symmetry)

They appear in logical statements (prenexes) when you want to make claims about all predicates of a kind or about the existence of some relation, without naming it:

su'o bu'a zo'u mi bu'a do There is some relation between me and you. (I relate to you somehow)

ro bu'a zo'u ganai da bu'a de gi de bu'a da For every relation: if A-relates-to-B then B-relates-to-A. (claim about all symmetric relations)

bu'a-series variables work exactly like da-series (bound by quantifiers in the prenex), but they fill the selbri slot rather than sumti slots.

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Anaphoric Pro-sumti and Pro-bridi: Full ri-series and go'i-series#

The ri-series back-references are based purely on recency in the discourse stream:

Key points:

• ri skips mi, do, and the ko'a/fo'a-series — but it does count ti/ta/tu (demonstratives), because you may have changed what you are pointing at since the last use.
• ri also skips zo'e, lerfu strings used as pronouns, and the ri/ra/ru words themselves.
• In la .teris. cu klama le zarci .i ri barda, ri = le zarci (the last completed sumti before ri), not la .teris.. Names with la are counted when they appear as complete sumti earlier in the string.
• Chaining: two ri in a row with no other sumti between them pick the same referent — see ri du ri above.

To avoid ambiguity in complex text, prefer explicit ko'a-assignments over ri.

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Summary#

• Names: end in consonant, written with pause marks .name., used after la
• Vocatives: coi (hello), co'o (bye), doi (O …), mi'e (I am …)
• la'e di'u = the situation described by the previous sentence (not the sentence itself)

Chapter 6. Questions & Answers#

Three Kinds of Questions#

Lojban has a dedicated particle for each type of question you might want to ask:

Each works by placing a question particle exactly where the answer would go.

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xu: Yes/No Questions#

xu is placed before any bridi to ask "Is this true?":

xu do klama le zarci Are you going to the store?

xu la .teris. cu tirxu Is Terry a tiger?

xu can also attach to a specific word to ask about just that part:

do xu klama le zarci Is it you that's going to the store? (questioning the "you" part)

do klama xu le zarci Is it the store that you're going to?

Answering xu questions:

The simplest affirmative answer is go'i (repeat the previous bridi as true) or simply je'u (indeed/truly):

xu do klama le zarci .i go'i Are you going to the store? — Yes [I am].

xu do klama le zarci .i je'u — Indeed.

The simplest negative is na go'i or na'i:

xu do klama le zarci .i na go'i — No [I'm not].

You can also give a corrective answer by restating the bridi with the correction:

xu do klama le zarci Are you going to the store?

mi klama le zdani [No,] I'm going home. (corrects both agent and destination)

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ma: Sumti Questions (Who/What/Where/When/Why)#

ma stands as a placeholder in any sumti slot and asks "what fills this slot?":

ma klama le zarci Who goes to the store? (ma in x₁ slot)

do klama ma Where are you going? (ma in x₂ destination slot)

do tavla mi fo ma What language are you speaking to me in? (ma in x₄ language slot)

do klama le zarci fi ma Where are you coming from? (ma in x₃ origin slot, tagged with fi)

Answers to ma questions are just the sumti that fills the slot:

do klama ma .i le zarci Where are you going? — The store.

ma klama .i la .teris. Who's going? — Terry.

Multiple ma in one sentence asks multiple questions at once:

ma tavla ma fo ma Who talks to whom in what language?

The listener must supply all three values in their answer.

Since ma can fill any sumti role, it serves for English's Who/What/Where/When/Why:

• Who → ma in x₁ of a person-expecting selbri
• What → ma in an object slot
• Where → ma in a location slot (or with a spatial tense)
• When → ma in a time slot (or with a temporal tense)
• Why → ma in a cause slot (ri'a + ma, or mu'i ma etc. — covered in Chapter 10)

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mo: Selbri Questions (What Relation?)#

mo stands where a selbri would be and asks "what relationship holds here?":

do mo What are you doing? / What relation holds with you in x₁?

ti mo What is this?

mo is quite open-ended — the listener must figure out which aspect of the relation is being asked about from context:

do mo .i mi tavla What are you doing? — I'm talking.

le gerku mo .i le gerku cu blabi What is the dog? — The dog is white.

When you need a more specific selbri question, use a tanru with mo in the tertau slot:

do klama ma mo You go to what kind of [place]? (mo asking about the type of destination)

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xo: Number Questions#

xo goes where a number would be and asks "how many?":

do ponse xo le cutci How many shoes do you own?

xo prenu cu klama How many people are going?

Answers give just the number:

do ponse xo le cutci .i mu How many shoes do you own? — Five.

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Indirect Questions#

Questions can be embedded inside a bridi as subordinate clauses. In Lojban, this uses the abstractor du'u (proposition) with kau marking the questioned element:

mi djuno lo du'u ma kau klama I know who is going. (indirect question: "who goes")

mi na djuno lo du'u xu kau do klama I don't know whether you are going.

mi djuno lo du'u do klama ma kau I know where you are going.

kau

marks the questioned element in an indirect question (turns a direct question word into an indirect one)

Indirect questions are covered in detail in Chapter 12 alongside other abstractions.

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fi'a: Place-Structure Questions#

From Chapter 4, recall fi'a asks which slot a sumti occupies:

fi'a do dunda le rozgu In what role are you involved in giving the rose?

Answered with: fa (you're the giver), fe (the gift), or fi (the recipient).

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Questions About Tense#

Tense particles have question-counterparts:

do klama le zarci cu'au ma When are you going to the store? (cu'au + ma questions tense)

More naturally, a tense question can be formed by using ma in a tense position:

do pu ma klama — but this isn't standard. The idiomatic form is to use the answer-question pair:

do ca ma klama le zarci When are you going to the store?

Temporal tense questions are covered more fully in Chapter 9.

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Answering Strategies#

Lojban answers can be:

A single sumti (for ma questions):

do klama ma .i le zdani Where are you going? — Home.

A selbri (for mo questions):

do mo .i mi citka What are you doing? — Eating.

go'i (repeat the bridi = yes):

xu do nelci lo mlatu .i go'i Do you like cats? — Yes.

na go'i (negate the bridi = no):

xu do nelci lo mlatu .i na go'i — No.

A corrected bridi:

xu do nelci lo mlatu .i mi nelci lo gerku Do you like cats? — No, I like dogs.

je'u (indeed, truly — emphatic yes):

je'u Indeed / Absolutely.

je'u nai (not indeed — emphatic no):

je'u nai Not at all / Certainly not.

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A Sample Dialogue#

coi .alis. .i do mo Hello, Alice. How are you? / What's up?

coi .djan. .i mi klama le zarci .i xu do klama Hi, John. I'm going to the store. Are you going too?

na go'i .i mi citka ca ti No. I'm eating right now.

do citka ma What are you eating?

lo cirla Cheese.

pluka .i xu do ponse xo le cirla Nice. How much cheese do you have?

mi ponse su'o ci le cirla .i mi na djuno lo du'u xo kau I have at least three pieces of cheese. I don't know exactly how many.

cu'e: Asking About Tense or Modal#

cu'e (selma'o CUhE) is the question word for tense and modal positions — it asks "what tense or circumstance applies here?":

do cu'e klama le zarci When / under what conditions do you go to the store?

The expected answer is a tense cmavo or modal tag:

mi ba klama (future) · mi pu klama (past) · mi ca klama (present) mi mu'i le nu mi djica klama (because I want to)

cu'e can replace any tense element in any position:

le verba cu cu'e sipna When is the child sleeping?

do cu'e litru How/when/why do you travel? — very open question about the circumstances of travel

When the question targets a modal specifically, the answer should be a BAI cmavo or fi'o phrase. When it targets a tense, the answer is a tense particle (pu, ca, ba, vi, va, vu, etc.).

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ji'a: "Also" in Answers to Connective Questions#

When answering a connective question (ji — "which one?"), the responder can use ji'a to mean "and also the other option":

do nelci lo mlatu ji lo gerku Do you like cats or dogs?

Answers:

lo mlatu — cats (only) lo gerku — dogs (only) lo mlatu .e lo gerku — both ji'a — and-also: the other one too (adds to a previous answer or implies both)

ji'a signals "in addition to what was already said/implied." It is a discursive that means "also, additionally":

mi klama le zarci .i ji'a mi klama le ckule I'm going to the store. I'm also going to the school.

While ji'a is not exclusively a question-answer word, it most naturally appears in contexts where an additional affirmative is being offered.

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mo in Embedded Bridi#

mo as a content question can appear inside du'u abstractions to ask about an embedded relationship:

mi djuno lo du'u do mo I know what you are / what relation holds for you.

xu do djuno lo du'u le gerku cu mo Do you know what the dog is?

The inner mo asks about the entire predicate relationship within the subordinate clause. The answer fills the embedded selbri position:

mi djuno lo du'u le gerku cu pendo I know that the dog is friendly. (pendo answers the embedded mo)

This pattern occurs with many knowledge and communication verbs that take du'u complements: djuno (know), cusku (say), jinvi (believe), smadi (guess).

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Summary#

• xu before a bridi → yes/no question; answered with go'i / na go'i / corrected bridi
• ma in a sumti slot → who/what/where question; answered with the appropriate sumti
• mo in the selbri slot → what-relation question; answered with a selbri
• xo in a number slot → how-many question; answered with a number
• kau marks the questioned element in indirect (embedded) questions
• fi'a asks which place a sumti occupies (answered with a FA particle)
• je'u = emphatic yes; je'u nai = emphatic no
• Whole-grammar Q&A roadmap (all question types, fa'u questions, legal non-bridi answers): Chapter 17

Chapter 7. Attitudes & Interjections#

What Are Attitudinal Indicators?#

In English, you convey emotion through tone of voice — but tone disappears in writing. Lojban handles this with attitudinal indicators (da'i words): dedicated particles that explicitly express attitude, emotion, and stance. They have no truth value of their own; they layer emotional color onto whatever is said.

Attitudinals can appear:

• At the start of an utterance — coloring the whole sentence
• After any word — coloring just that word

.ui la .teris. cu klama [Yay!] Terry is coming!

la .teris. .ui cu klama Terry [yay!] is coming. (happiness is about Terry specifically)

la .teris. cu klama .ui Terry is coming [yay!] (happiness is about the coming specifically)

All attitudinals can be negated with -nai (opposite) or neutralized with -cu'i (neutral/indifferent).

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How the pieces fit together (scales and domains)#

CLL pictures the attitudinal system as a small space you move in, not a flat list of particles. In practice you combine:

Any layer can be skipped: .ui alone is already a full utterance. The geometry is just a map — it helps you see that .uicai is “same emotion, higher volume,” and .uiro'e is “same happiness, but about an idea.”

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Pure Emotion Indicators#

These express the speaker's feelings about the world as it is. The u-series are the simplest:

.ui mi facki fi le mi mapku [Yay!] I found my hat!

.ue la .teris. cu klama [Wow!] Terry is coming!

.uenai la .teris. cu klama [Of course.] Terry is coming. (it was expected)

.uu do cortu [Poor you.] You're in pain. (sympathy)

.u'u do cortu [I'm sorry.] You're in pain. (guilt/repentance — I feel responsible)

Note the distinction between .uu (sympathy — it's not my fault) and .u'u (repentance — I feel partly responsible). Both can be translated "I'm sorry" in English.

The o-series covers more complex or ambivalent emotions:

.oi la .djan. klama [Ugh!] John is coming. (complaint about it)

.o'onai la .djan. klama [Angry!] John is coming. (anger)

.o'u mi facki fi le mi mapku [Phew!] I found my hat. (relief)

The i-series (pure emotions) includes:

.ii smacu [Eek!] A mouse!

la .djan. .iu klama John [love!] is coming. (speaker loves John)

la .djan. .ionai klama That good-for-nothing John is coming. (disrespect for John)

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Propositional Attitude Indicators#

These express the speaker's attitude toward a potential state of affairs — not just a feeling but an orientation (intent, hope, desire, belief, etc.):

.ai mi klama le zarci [I intend to] go to the store. (signals intent, not just prediction)

.au mi sipna [I want to] sleep.

.a'o mi kanryze'a [Hopefully] I'll feel better.

.a'ucu'i do pante [No interest] you complain. = I have no interest in your complaints.

The e-series covers more complex propositional attitudes:

.e'o ko klama [Please] come here! (polite request)

.e'a ko citka [Permission:] Go ahead and eat!

.ei mi viska le cukta [I should] read the book.

.e'u mi'o klama le zarci [Suggestion:] Let's go to the store.

Finally, the i-series propositional attitudes (overflow from the a/e sets):

.ianai do pu pensi le nu tcica mi [Disbelief!] You thought you could fool me.

.ie mi cusku [Agreement] — I said it too.

.i'enai do .i'e zukte I don't approve of what you did, but I approve of you (the latter attitudinal attaches to do).

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Intensity Markers (CAI)#

Every attitudinal sits on a seven-point scale. The scale runs from maximal positive through neutral to maximal negative. You express your position on the scale by appending a CAI cmavo directly to the attitudinal:

.uicai mi facki [ECSTATIC!] I found it!

.uiru'e mi facki [Mildly pleased.] I found it.

.uicu'i = I feel neither happy nor unhappy about it.

.uinai = unhappy; .uinaicai = absolutely miserable.

Using CAI without an emotion word acts as a pure emphasis/de-emphasis marker:

cai alone = [strongly!] — emphasizes whatever follows cu'i alone = [whatever] — signals indifference

Applied to .ei (obligation), the scale captures English modal distinctions precisely:

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Evidential Indicators#

Evidentials say how the speaker knows or relates to what they're claiming. A bridi marked with an evidential becomes indisputable in a useful sense — you're reporting your own epistemic state, which no one else can directly contradict.

za'a la .teris. cu klama [I see that] Terry is coming.

ti'e la .teris. cu klama [I heard that] Terry is coming.

pe'i le nu do tavla cu xlali [In my opinion] your talking is bad.

ja'o mi bilma [Therefore] I am sick. (concluded from symptoms)

ca'e le vi mlatu cu barda [I hereby declare] this cat is big. (defining it so)

ba'acu'i le tuple be mi cu se cortu [I experience] my leg hurts. (direct sensation, present tense on the ba'a scale)

ru'a doi livinston. Dr. Livingstone, I presume?

Ask about evidentials with ju'apei: What is the basis for your claim?

Evidentials often appear at the start of a sentence or attached to .i in running discourse.

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Discursive Indicators#

Discursives comment on the structure of the discourse — how this utterance relates to what was said before or after. Unlike attitudinals, they express no particular emotion.

Consecutive discourse (how this relates to the previous statement):

mi klama le zarci .i ku'i mi na ponse lo jdini I'm going to the store. However, I have no money.

la .alis. cadzu .i si'a la .djan. cadzu Alice walks. Similarly, John walks.

mi po'o darxi le mi tamne Only I hit my cousin. (no one else did)

Commentary on words (how words are being used):

mi cadzu .i va'i mi klama lo stuzi vau lo jamfu I walk — in other words, I travel somewhere on foot.

Commentary on discourse (the nature of what's being said):

.zo'o mi klama le solri [Just kidding:] I'm going to the sun.

.ba'u mi ponse pa milono cutci [Exaggerating:] I own a million shoes.

.je'unai le tcati cu glare [Sarcastically:] The tea is hot. (it's cold)

sa'e le cinfo cu xabju le sruri be le xamsi Precisely speaking, the lion lives in the savanna surrounding the sea.

Knowledge (speaker's certainty):

ju'o la .djan. klama John is certainly coming.

la'a mi morsi I'm probably dying. (dramatic but useful example)

Discourse management (navigating the flow):

ta'o mi pacna lo nu do klama By the way, I hope you come.

ra'u mi na djica le nu do klama Most importantly, I don't want you to come.

mu'a le zarci .e le briju For example, the store and the office.

da'i do viska le mi mensi .i xu do nelci ri Suppose you saw my sister — would you like her? (hypothetical framing)

ganai da'i do viska le mi mensi If [hypothetically] you saw my sister… (counterfactual)

ganai da'inai do viska le mi mensi If [in reality] you see my sister… (open conditional)

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Emotion Category Modifiers (ro'a-series)#

The ro'a-series modifiers attach after any attitudinal to specify which domain of experience the feeling belongs to. They multiply every attitudinal into six more specific variants:

Combine after an attitudinal (and after any intensity marker):

.o'unairo'o = physical discomfort (.o'u = comfort/relaxation, nai = negative, ro'o = physical)

.oinairo'a = social frustration / irritation

.uiro'e = intellectual joy / delight in an idea

.o'unaire'e = spiritual discomfort (e.g. feeling out of place in the wrong church)

.eiro'u = sexual obligation — a uniquely Lojbanic emotional label with no direct English word!

You can also use category words alone, without specifying an emotion:

ro'e = I'm concentrating / it's a mental matter ro'anai = I'm feeling antisocial

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Attitudinal Modifiers#

Beyond categories, there are eight attitudinal modifiers that refine how an emotion is experienced or expressed. They combine after an emotion+intensity string:

Examples:

.ause'i = [want-self] = I want it for myself! .ause'inai = [want-other] = I want you to have it!

.uuse'i = self-pity .uuse'inai = pity for others

.o'onai ri'enai = suppressed anger (I'm furious, but holding it in) .o'onai ri'e = openly expressing anger

.e'ese'a = I can do it all by myself! .e'ese'anai = I can do it if you help me.

ko ga'inai nenri klama le mi zdani [I regard you as superior] Please enter my home. (very formal/deferential)

ko ga'i nenri klama [I regard you as inferior] Get inside! (imperious)

ga'i attaches to the referent, not the speaker — so attach it to a sumti to mark it:

doi ga'inai appended to any statement = [addressing a social superior]

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Attitude Questions, Empathy, and Contours#

pei — attitude question: "How do you feel?" / "Do you feel X?"

pei alone = How are you feeling? / How do you feel about that? .iepei = Do you agree? (asking about agreement) .aipei = Are you going to do it? (asking about intent) .e'apei = May I? / Can I please?? (asking for permission) pei.o'u = Are you comfortable?

Respond with a CAI marker: .iepei → .iecai = Yes, absolutely!

dai — empathy: attributes the preceding attitudinal to someone else, not the speaker:

.oiro'odai = [Pain-physical-empathy] = Ouch, that must hurt! (empathizing with their pain)

le bloti .iidai .uu pu klama le xasloi The ship, fearfully, poor thing, sank to the ocean floor. (.ii is attributed to the ship via dai; .uu is the speaker's own pity)

bu'o — attitude contour: whether you are starting, continuing, or ceasing to feel an emotion:

.o'onai bu'o = I'm getting angry! .iu bu'onai .uinai = I don't love you anymore; I'm sad.

Note that .ui .ui .ui ≠ .uicai — repeating an attitudinal means the feeling continues, not that it intensifies.

ge'e — the non-specific emotion placeholder:

• Used to express some feeling without naming it: ge'e = I feel something (but won't say what)
• Used to separate two emotion strings so a modifier doesn't bleed across: .ui ge'eru'e = happiness (at unspecified level) + some weak unspecified feeling
• .iige'e = I'm not saying whether I'm afraid or not

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Miscellaneous Indicators#

Some indicators fit no single category:

ki'a is among the most-used: it marks that you heard the words but don't understand their referent or meaning:

mi nelci le ctuca I like the teacher. le ctuca ki'a Which teacher? / The teacher — (confused)

na'i marks a false presupposition or grammatical/factual error in what was said:

xu do klama = Is it true that you're going?

bi'u helps with reference tracking in narrative:

le bi'u nanmu = a man (new, not yet mentioned) le bi'unai nanmu = the man (previously referred to)

fu'e / fu'o: Cross-Sentence Attitudinal Scope#

Normally an attitudinal colors only the word (or sentence) it follows. But sometimes you want a single attitudinal to govern a whole passage — multiple consecutive sentences. fu'e opens an attitudinal scope and fu'o closes it:

fu'e .ui [Start happiness scope]

la .teris. cu klama .i le zarci cu melbi .i mi ponse le mi plise Terry comes. The store is beautiful. I have my apple.

fu'o [End happiness scope — all three sentences above were colored by .ui]

Without fu'e/fu'o, you would need .ui before every sentence in the passage.

Rules:

• fu'e must be immediately followed by an attitudinal (possibly stacked): fu'e .ui .o'u opens both happiness and relaxation.
• fu'o closes all currently open fu'e scopes (there is no matched-pairs system — a single fu'o closes everything).
• A new fu'e inside an open scope replaces the current scope with the new one.
• Attitudinals used within an open scope attach normally to individual words and don't affect the scope.

fu'e .oi [Complaint mode on] le zarci cu vimcu .i le karce cu spofu .i lo crino mlatu cu batci mi The store is closed. The car is broken. A green cat bit me. fu'o [End complaint scope]

All three sentences are colored by .oi (complaint/ugh).

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Vocative Indicators: Full COI Catalogue#

Vocatives (selma'o COI) are used to directly address someone, establish conversational roles, or manage communication protocol. Unlike pure attitudinals, they typically precede a name (without la) or description; do'u is the elidable terminator.

doi is the general-purpose address particle, not a scale — just doi + name:

doi .djan. — Hey John! / O John!

All COI members require a pause before a name to prevent the name absorbing the cmavo (write with a period: coi .djan.); or insert doi between them: coi doi djan.

Most COI cmavo form scales with nai (opposite) and sometimes cu'i (neutral/standby). These signal conversational state, especially in structured/radio communication.

mi'e is unique — it identifies the speaker, not the listener:

mi'e .djan. — I am John. mi'enai .djan. — I am not John. (denying an attribution) fe'omi'e .djan. — Signing off, this is John. re'imi'e .djan. — Ready, this is John. (e.g., answering roll-call)

The last COI in a chain controls whose name follows: if mi'e is last, the name is the speaker's; otherwise it's the listener's.

Selected examples:

coi .alis. — Hello, Alice. co'o — Goodbye. ju'i — Attention! / Hey! ju'icu'i — At ease. / Stand down. ju'inai — Dismissed. ki'e do — Thank you. ki'enai — You're welcome. / No thanks. fi'i .djan. — Welcome, John. / Come in, John. fi'inai — You are not welcome. be'e — May I speak? / Request to speak. be'ecu'i — Stand by. be'enai — Don't speak. / Not now. je'e — Roger. / Understood. je'enai — Negative. / Not understood. vi'o — Wilco. / Will comply. vi'onai — Will not comply. mu'o — Over. (done transmitting) mu'ocu'i — (pausing mid-speech) mu'onai — I'm not done yet. ke'o — Please repeat. / Say again. fe'o — Over and out. / Signing off. ta'a — I interrupt. / Excuse me, I need to speak. ta'anai — I yield the floor. / Go ahead. nu'e mi klama — I promise I'll come. nu'enai — I won't. / I refuse.

ta'a mi djica lo nu cusku [Interrupt] I want to say something.

ta'anai doi .frank. I yield to you, Frank.

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Scalar vocatives: quick “radio-style” flows#

Many COI cmavo form scales (plain / cu'i / nai). In real conversation they often appear in pairs — interrupt vs yield, request vs grant, over vs still talking:

These are the same words as in the table above; the extra value is seeing them as protocol slots, not isolated greetings.

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A short dialogue (attitudinals + vocatives)#

Terry and Alice meet at a workshop. (In running Lojban text you would often mark the speaker with sei la … cusku — see Chapter 17 — here we label lines in English for readability.)

Terry: coi doi .alis. — Hello, Alice.

Alice: .uicai coi doi .teris. — [Delighted] Hi, Terry!

Terry: pei do gleki — How do you feel? / Are you happy?

Alice: .iecai .i .e'u mi'o pinxe lo ckafi — Absolutely. Let’s get coffee [suggestion].

Terry: je'e .i ki'e .i mu'o — Understood. Thanks. Over.

Alice: ta'anai .i fe'o — Go ahead [continue]. Signing off [playful, or end of side-channel].

This is not a full-length scene — it only shows coi, .ui, pei, .ie, .e'u, je'e, ki'e, mu'o, ta'anai, fe'o strung together. Extend it with .oi, evidentials, or more COI as you learn them.

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sei … se'u: Speaker attribution in running text#

sei (selma'o SEI) lets you embed a comment about the utterance itself without making it part of the bridi's truth conditions. The most common use is speaker-tagging in dialogue transcripts:

.i sei la .teris. cusku se'u (sentence) — [comment] Terry says [end-comment]

The sei … se'u frame is parenthetical: it does not change what the sentence asserts. se'u closes the frame; it can be omitted when the end is unambiguous, but keeping it is clearest.

A coffee-bar scene with sei-tagging:

la .teris. joi la .alis. nerkla le kafybarja Terry and Alice go into the coffee bar together.

.i sei la .teris. cusku se'u ta'a ro zvati .i mi ba speni la .alis. .iu Terry said, interrupting all present: “I’m going to marry Alice, my love.”

.i sei la .alis. cusku se'u nu'e .djan. do ba zvati le nu mi spenybi'o Alice said: “I promise you, John — you’ll be at the wedding.”

.i sei la .djan. cusku se'u ki'e cai John said: “Thank you so much!”

.i sei le selfu cu cusku se'u re'i The server said: “Ready to take your order.”

.i sei la .teris. cusku se'u fi'i ro zvati .i ko pinxe pa ckafi fi'o pleji mi Terry said: “Welcome, everyone. A round of coffee, on me.”

.i sei le selfu cu cusku se'u vi'o The server said: “Will do.”

Grammar note: sei can appear anywhere inside a sentence — not just between sentences. It is a member of selma'o SEI; se'u is in selma'o SEhU. Both are covered in the text-structure section of Chapter 17.

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Summary#

• Attitudinals are particles expressing feeling, attitude, or epistemic stance — no truth value of their own
• Families × polarity × intensity (CAI) × domain (ro'a-series) — the “geometry” of the system; only the first layer is mandatory
• Attach after any word to color it; at sentence start to color the whole sentence
• -nai = opposite polarity; -cu'i = neutral/cancel; -cai/-sai/-ru'e = intensity scale (7 positions)
• u-series = simple emotions; o-series = complex/ambivalent; i-series (pure) = fear, solidarity, love, etc.
• a/e/i-series (propositional) = intent, desire, request, obligation, belief, agreement
• ro'a-series = category modifiers: social/mental/emotional/physical/sexual/spiritual
• Attitudinal modifiers: ga'i (rank), le'o (aggression), vu'e (ethics), se'i (self/other), ri'e (release), fu'i (assistance), be'u (sufficiency), se'a (self-sufficiency)
• pei = attitude question; dai = empathy; bu'o = attitude contour; ge'e = unspecified
• Evidentials (ja'o ca'e ba'a su'a ti'e ka'u se'o za'a pe'i ru'a ju'a) — source of knowledge
• Discursives — 5 groups: consecutive, word-commentary, discourse-commentary, knowledge, management
• Misc: ki'a (confused), na'i (wrong), jo'a (correct despite appearance), xu (truth question), bi'u (new referent)
• Vocatives (selma'o COI) manage the conversational frame; doi = general address particle (no scale); scalar COI often come in protocol pairs (e.g. ta'a / ta'anai)

Full COI catalogue (most form nai/cu'i scales):

• coi = hello; co'o = goodbye
• ju'i = attention! / ju'icu'i = at ease / ju'inai = dismissed
• ki'e = thank you / ki'enai = you're welcome
• fi'i = welcome / fi'inai = unwelcome
• mi'e = I am [name] (identifies speaker, not listener) / mi'enai = I am not [name]
• be'e = request to speak / be'ecu'i = standby / be'enai = don't speak
• re'i = ready/listening / re'icu'i = standby / re'inai = not ready
• mu'o = over (done) / mu'ocu'i = pausing / mu'onai = not done
• je'e = roger/understood / je'enai = negative/not understood
• vi'o = wilco/will comply / vi'onai = will not comply
• ke'o = please repeat / ta'a = I interrupt / ta'anai = I yield
• nu'e = I promise / nu'enai = I refuse; pe'u = please; fe'o = signing off
• Last COI in a chain governs whose name follows; mi'e last = speaker's name
• sei … se'u = parenthetical metalinguistic comment (speaker-tag in dialogue); does not affect bridi truth conditions

Chapter 8. Connecting Ideas#

The Four Basic Logical Operations#

Lojban has a systematic set of words for connecting two claims logically. The logic is truth-functional: the truth or falsehood of the combined claim depends only on the truth or falsehood of the parts.

Four basic operations cover almost all everyday needs:

Reading truth tables: the four rows represent the four cases (TT, TF, FT, FF — first-true/second-true, first-true/second-false, etc.). The result column shows whether the combined claim is true in each case.

So A (or) is true in three of four cases — whenever at least one component is true. E (and) is only true when both are true. O (iff) is true when both match.

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Connecting Whole Sentences (ijeks)#

The simplest connection is between two complete sentences. The connective goes between them, starting with .i:

la .alis. cu klama .ije la .djan. cu cadzu Alice comes and John walks.

mi citka lo plise .ija mi citka lo perli I eat an apple or I eat a pear.

mi gleki .iju do klama I'm happy whether or not you come.

Negating inside the connective:

Add na before the vowel to negate the first sentence's contribution; add -nai after the vowel to negate the second:

mi citka .ijanai mi pinxe I eat or I don't drink. (= "I eat if I drink")

mi citka .inaja mi pinxe I don't eat or I drink. (= "If I eat, then I drink")

The most useful derived form is .inaja (if-then, material conditional):

mi klama .inaja do klama If I go, then you go.

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Forethought Connection: ga … gi#

The afterthought form above adds the connective after the first sentence. The forethought form signals the connection before the first sentence:

ge la .alis. cu klama gi la .djan. cu cadzu Both Alice comes and John walks.

ga mi citka gi mi pinxe Either I eat or I drink.

ganai mi klama gi do klama If I go, then you go.

Forethought is stylistically cleaner for if-then constructions, since it avoids the appearance of asserting the first sentence and then qualifying it.

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Connecting Sumti (eks)#

To connect two arguments (rather than whole sentences), use eks — bare vowel letters (possibly with na/nai):

la .alis. .e la .djan. cu klama Alice and John come.

mi citka lo plise .a lo perli I eat an apple or a pear.

mi tavla la .alis. .e la .djan. I talk to Alice and to John.

Note: .e between sumti is not the same as .ije between sentences. la .alis. .e la .djan. cu klama means "Alice comes and John comes (separately)" — it expands to two bridi. You cannot use .e to mean "together" — that would be joi (see below).

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Connecting Selbri (jeks)#

To connect two relation words (selbri) in a single bridi, use jeks — formed with j + vowel:

la .teris. cu tirxu je blabi Terry is a tiger and white. (= both a tiger and white)

le mlatu cu melbi ja pluka The cat is beautiful or pleasant.

mi sutra je clani I am fast and tall.

Jeks are most commonly seen as je, connecting two properties of the same x₁.

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Non-Logical Connectives#

Not every "and" is logical. Sometimes you want to say things are together or form a sequence rather than just both being true:

joi — "in a mass together with"

Combines two sumti into a joint mass acting as one.

mi joi do cu bevri le pipno You and I (together as a unit) carry the piano. (neither of us alone)

joi is the connective behind mi'o (= mi joi do). It's used when the components cooperate as a collective, not when each individually satisfies the relation.

jo'u — "jointly, in common"

Expresses a shared relationship.

mi jo'u do cu simxu le ka prami You and I mutually love (each other).

ce — "and (in a set)"

Creates a set sumti from two members.

mi ce do cu gunma You and I form a group/set.

fa'u — "respectively"

Parallel assignment — first to first, second to second.

la .alis. fa'u la .djan. cu klama fa'u cadzu Alice goes, John walks (respectively). (Alice-goes, John-walks in parallel)

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Connecting in Context: Scope#

When you connect in different positions, the scope changes:

Sentence-level (.ije):

mi klama .ije do cadzu I go and you walk. (two independent claims)

Sumti-level (.e):

mi .e do cu klama I and you go. (same claim, both of us going)

Selbri-level (je):

mi klama je cadzu I go and walk. (I do both to the same destination)

All three are logically equivalent when the sumti/selbri being connected share all other slots — but they differ in emphasis and brevity.

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The to'e Opposite#

A useful related particle: to'e placed before a selbri or brivla gives its opposite:

to'e melbi ugly (opposite of beautiful)

to'e klama not-going / staying away

to'e is not a connective but pairs well with je:

le zarci cu barda je to'e melbi The store is big and ugly.

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na'e and No'e: Scalar Negation#

Related to negation and connection, these words mark positions on a scale:

na'e — "other than, non-"

x₁ is not the default value; some other value holds.

mi na'e klama I do something other than go. (not necessarily the opposite — maybe I stay, maybe I run)

no'e — "midpoint, neutral"

Approximately the middle of the scale.

le cukta cu no'e barda The book is medium-sized. (neither big nor small)

to'e — opposite end of the scale.

These three together form a scalar system: no'e (neutral) → na'e (non-default) → to'e (opposite). Full negation logic is covered in Chapter 13.

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Why Are There Six Connective Positions?#

This is a grammar-derived question that trips up many learners. The answer is that each connective position corresponds to a different level in the parse tree. Using the wrong class at a given level either produces a grammar error or silently changes the meaning.

Here is the full map:

Why it matters — two examples that look similar but mean different things:

mi .e do cu klama — x₁ = [mi and do]; one bridi, we both go mi klama .ije do klama — two separate bridi; I go, and you go

Both translate as "I and you go" in English, but they are grammatically different. The .e version has a compound x₁; the .ije version makes two independent claims.

mi klama je cadzu le zarci — I go-and-walk to the store (both go and walk, same destination) mi klama .ije mi cadzu le zarci — I go to the store. I walk to the store. (two claims)

The gihek shortcut: When the same x₁ does two things, gi'e is more concise than .ije:

mi klama le zarci gi'e facki lo cukta I go to the store and find a book. (same I, two actions)

This is shorter than mi klama le zarci .ije mi facki lo cukta and explicitly marks that the same x₁ is doing both things.

Chaining several tails: giheks associate left to left — each new tail still shares the same x₁, but may introduce its own trailing sumti:

mi klama le zarci gi'e cadzu le dargu gi'e pinxe lo jisra I go to the store, walk on the road, and drink the juice. (one mi, three predicates)

The first place of cadzu is the walker (mi); le dargu is the route. If a later tail needs a different x₁, you cannot use gihek — split into .ije sentences or rephrase.

Forethought: The ge…gi family signals the connective before the first element. This is useful when you want "if-then" without apparently asserting the antecedent:

ganai mi klama gi do klama — If I go, then you go.

Compare to the afterthought .inaja, which puts the connective between them — by the time you hear the connective, the first claim has already been made.

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Where to go next (tense, modals, mekso, abstractions)#

Logical connectives interact with other grammar in dedicated sections:

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Grouping Afterthought Connectives: bo#

Afterthought connectives follow the left-grouping rule: A .ije B .ije C = (A and B) and C. When you want different grouping — A and (B or C) — append bo to the connective that should bind tighter:

mi nelci la djan. .ije mi nelci la martas. .ijabo mi nelci la meris. I like John, and (I like Martha or I like Mary).

The .ijabo binds the Martha/Mary clause first. Without bo, .ija would left-group with the previous .ije.

The same works for sumti connectives:

mi dzukla le zarci .e le zdani .abo le ckule I walk to the market and (the house or the school).

For bridi, explicit parentheses with tu'e…tu'u are clearer for complex nesting:

tu'e mi cinba do .ije do cinba mi tu'u .ijo tu'e mi prami do .ije do prami mi (I kiss you and you kiss me) if-and-only-if (I love you and you love me).

Key rules for bo-grouping:

• bo after a connective = bind tighter than unmarked connectives
• Multiple consecutive bo-marked connectives = right-grouping among themselves
• For three or more clauses, tu'e…tu'u (sentences) or ke…ke'e (sumti/tanru) are cleaner

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Termsets: Connecting Multiple Places at Once#

When two bridi differ in more than one sumti simultaneously — not just one argument but two — termsets let you connect them compactly.

A termset groups terms together using ce'e (selma'o CEhE) between them. The logical connective is prefixed by pe'e (selma'o PEhE):

mi klama le zarci ce'e le briju pe'eje le ckule ce'e le zdani I go [to the market from the office] and [to the school from the house].

The pairs le zarci + le briju (destination + origin) and le ckule + le zdani are the two termsets. Without ce'e, linking the sumti separately would be ambiguous about which destination pairs with which origin.

Expanding shows what this means:

mi klama le zarci le briju .ije mi klama le ckule le zdani I go to the market from the office, and I go to the school from the house.

Forethought termsets use nu'i (opening bracket) and nu'u (closing bracket, elidable), with a gek inside:

mi klama nu'i ge le zarci le briju nu'u gi le ckule le zdani I go [both to the market from the office] [and to the school from the house].

Termsets appear in several other contexts too: in tense coordination (CLL §10.25) and quantifier scope (CLL §16.7).

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Connective Questions: ji, je'i, gi'i, ge'i, gu'i#

To ask which connective applies between two things — not just whether the combined statement is true, but what the logical relationship is — Lojban uses special question cmavo that stand in for a connective:

do djica loi ckafi ji loi tcati Do you want coffee [what-connective?] tea?

A yes/no question with xu would ask whether a specific relationship holds. A ji question asks you to specify the connective. Possible answers:

.e — both coffee and tea .a — either one (you choose) .onai — one but not both (exclusive or)

la .alis. gerku gi'i mlatu Is Alice a dog [what-connective?] a cat?

Answers: gi'enai (dog but not cat), nagi'e (cat but not dog), nagi'enai (neither), gi'e (both — unusual but possible). The answer nagi'o ("one or the other but I won't say which") is technically valid but uncooperative.

je'i asks which JA cmavo belongs between two tanru pieces (the same slots where je, ja, jonai, … appear):

mi sutra je'i masno cadzu I quickly [which connective?] slowly walk?

Plausible answers: je (both modifiers apply), ja (one or the other), jonai (exactly one), and so on — each is a bare JA, like answers to ji/gi'i.

ge'i and gu'i ask which GA or GUhA starts a forethought connection. They are grammatical, but you should not answer with an isolated ge/gu'e/ga/gu'a … — that would sound like the beginning of a new forethought bridi. Use the afterthought connective instead (e.g. .e, gi'e, je); the connective questions summary is above in Chapter 8.

ge'i mi klama le zarci gi mi klama le zdani [Which GA?] I go to the market, I go to the house?

gu'i sutra gi masno cadzu [Which GUhA?] quick, slow walk? (forethought version of the je'i pattern above)

The answer to ji / je'i / gi'i is simply the bare connective — grammatically valid on its own. For ge'i / gu'i, prefer the same connective in afterthought shape.

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Interval Connectives: bi'i, bi'o, mi'i#

The selma'o BIhI provides three connectives for specifying intervals — ranges between two endpoints. These are non-logical connectives used in the same positions as JOI.

bi'i (order doesn't matter):

mi ca sanli la drezdn. bi'i la frankfurt. I am standing between Dresden and Frankfurt.

The interval is symmetric — "between Dresden and Frankfurt" = "between Frankfurt and Dresden."

bi'o (order matters):

mi cadzu ca la pacac. bi'o la recac. I walk from 1 o'clock to 2 o'clock.

Here la pacac. must come before la recac. — reversing them gives an 11-hour interval. Use sebi'o to reverse the direction: from 2 to 1.

mi'i (center + radius):

le jbama pu daspo la .uacintyn. mi'i lo kilto be li mu no The bomb destroyed [an area centered on] Washington within 50 km.

Endpoint inclusion: ga'o and ke'i#

By default, bi'i/bi'o are ambiguous about whether the endpoints are included. The GAhO cmavo specify this:

They appear on both sides of the BIhI cmavo, each applying to the adjacent endpoint:

la drezdn. ga'o bi'i ga'o la frankfurt. Between Dresden and Frankfurt, inclusive of both endpoints.

la drezdn. ke'i bi'i ke'i la frankfurt. Strictly between Dresden and Frankfurt, excluding both cities.

la pacac. ga'o bi'o ke'i la recac. From 1 o'clock (inclusive) to 2 o'clock (exclusive). (the hour doesn't include its endpoint)

A negated interval with -nai means everything outside that range:

do dicra .e'a mi ca la daucac. bi'onai la gaicac. You may disturb me at times outside 10–8 (i.e., not during those hours).

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Summary#

Cross-links: tense + connective → Ch.16; modal + .ije… → Ch.10; mekso → Ch.18; abstractor connection → Ch.12.

Sentence connectives (ijeks): placed between full bridi

• .ije = and; .ija = or; .ijo = iff; .iju = whether-or-not
• .inaja = if-then (negate first); .ijanai = or-not-second

Bridi-tail connectives (giheks): share x₁ between two predicates

• gi'e = and; gi'a = or; gi'o = iff; gi'u = whether-or-not
• Chains (gi'e … gi'e …) = several tails for one x₁; each tail may have its own following sumti

Forethought connectives (geks): signal connection before first bridi

• ge…gi = both…and; ga…gi = either…or; ganai…gi = if…then

Forethought selbri (guheks): forethought within tanru

• gu'e…gi = both…and; gu'a…gi = either…or

Sumti connectives (eks): between arguments

• .e = and; .a = or

Selbri connectives (jeks): between relation words

• je = and; ja = or

Non-logical: joi (mass together), jo'u (jointly), ce (set-forming), fa'u (respectively)

Scalar: na'e (non-), no'e (middle), to'e (opposite)

Grouping afterthought connectives:

• Default is left-grouping: A .ije B .ije C = (A and B) and C
• bo appended to a connective binds tighter: .ijabo = bind-right
• tu'e…tu'u = explicit bridi parentheses for complex nesting

Termsets (connecting multiple places at once):

• ce'e = joins terms within one termset; pe'e + jek = the connective
• nu'i…nu'u = forethought termset brackets

Connective questions (ask which connective, not truth value):

• ji (A) = sumti connective question: coffee ji tea?
• je'i (JA) = tanru connective question (mi sutra je'i masno cadzu)
• gi'i (GIhA) = bridi-tail connective question
• ge'i (GA) / gu'i (GUhA) = forethought connective questions; answers use afterthought connectives (see section above)
• Answer with a bare connective: .e, gi'enai, je, …
• Full question-answer protocol (including ma fa'u ma): Chapter 17

Interval connectives (selma'o BIhI — non-logical):

• bi'i = unordered interval (between); endpoints interchangeable
• bi'o = ordered interval (from…to); sebi'o = reversed
• mi'i = center-and-radius interval
• ga'o = inclusive endpoint; ke'i = exclusive endpoint
• bi'onai = everything outside the interval

Chapter 9. Time & Space#

Tense Is Optional#

Lojban bridi carry no mandatory tense. The sentence mi klama le zarci can mean "I went", "I go", "I will go", or "I habitually go" — context decides which. This is deliberate: you only add tense information when it matters to the conversation.

When you do want to specify time, place a tense particle immediately before the selbri (or right after cu):

mi pu klama le zarci I [past] go to the store. → I went to the store.

mi ca klama le zarci I [now] go to the store. → I am going to the store.

mi ba klama le zarci I [future] go to the store. → I will go to the store.

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The Three Time Directions: pu, ca, ba#

pu

(particle) before now / in the past

ca

(particle) at the same time / now / present

ba

(particle) after now / in the future

These three are the heart of Lojban's tense system. They come from the gismu purci (past), cabna (present), and balvi (future).

la .teris. pu klama le barda tcadu Terry went to the big city.

la .teris. ba sipna Terry will sleep.

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Time Distances: zi, za, zu#

Add a ZI particle after the direction to say how far in the past or future:

zi

short time distance (moments ago / soon)

za

medium time distance (hours, days, a while)

zu

long time distance (years, ages)

Combine direction + distance:

mi puzi citka I ate a short time ago. (recently)

mi puzu citka I ate a long time ago.

mi bazi klama I'll go very soon.

mi bazu klama I'll go a long time from now.

The distance words alone, without a direction, indicate "near/far in time but unspecified direction":

mi zi klama I go/went/will go close to now. (around now, not exactly now)

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Time Intervals: ze'i, ze'a, ze'u#

The ZEhA particles describe how long the event lasts, rather than when it happens:

ze'i

short time interval (briefly)

ze'a

medium time interval (for a while)

ze'u

long time interval (for a long time)

mi ze'u sipna I sleep for a long time.

le verba pu ze'a cadzu le bisli The child walked on the ice for a while.

Interval words come after direction words:

mi pu ze'a citka I was eating for a while [in the past].

You can also specify where in the interval the reference point falls by adding another direction after the interval:

mi ca ze'ica cusku dei I am [now, short-interval spanning now] saying this. → I am now saying this sentence.

mi ca ze'ipu cusku dei I have just been saying this. (interval extends into the past from now)

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Tense Scope: ku#

Normally a tense particle before the selbri applies to that bridi. To move it elsewhere for emphasis, add ku after it:

puku mi klama le zarci Earlier, I went to the store. (pu emphasized at the front)

mi klama le zarci puku I went to the store [earlier]. (pu at the end)

ku after a tense is an elidable terminator. At the end of a bridi it can usually be dropped.

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Space Tenses: vi, va, vu and FAhA#

Lojban has spatial tenses too, working exactly like temporal ones. Think of them as an imaginary journey from the speaker to where the event happens.

Distance (VA):

vi

short distance / here

va

medium distance / nearby

vu

long distance / over there / far away

vi, va, vu work as spatial sumti tcita: they take a location landmark as their argument, just as pu/ca/ba take a time argument.

le ratcu cu citka le cirla vi le panka The rat eats the cheese near the park.

le ratcu cu citka le cirla vu le vi panka The rat eats the cheese far from the nearby park.

Direction (FAhA): specifies which way to travel

Direction before distance:

le nanmu zu'a batci le gerku To my left, the man bites the dog.

le nanmu zu'avi batci le gerku A short distance to my left, the man bites the dog.

Compound spatial tenses chain journeys:

le nanmu ga'u zu'a batci le gerku Left of a place above me, the man bites the dog. (go up, then go left)

Space intervals (VEhA):

ve'i

small space interval

ve'a

medium space interval

ve'u

large space interval

le verba ve'i cadzu le bisli The child walks on the ice in a small area.

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Combining Time and Space#

When both time and space tenses appear in one bridi, time comes first:

le nanmu puzu vu batci le gerku Long ago and far away, the man bit the dog.

mi bazi vi klama I'll go here soon.

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Aspect: co'a, co'i, ca'o, co'u#

Aspect describes the shape of an event — is it beginning, in-progress, or complete? Aspect particles also go before the selbri (or after a tense particle):

co'a

begins / starts (inchoative)

ca'o

continues / is ongoing

co'u

ends / stops

co'i

completes / perfective

mo'u

reaches endpoint / finishes

za'o

continues past its natural endpoint (excessive)

la .teris. co'a cadzu Terry starts walking.

mi ca'o citka I am (continuously) eating.

le nu klama cu co'i The going is/has completed.

mi co'u tavla I stopped talking.

From the Terry story:

la .teris. co'a cadzu klama le bi'unai barda tcadu Terry started walking to the big city.

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Tense in Subordinate Clauses#

Tenses in embedded clauses are relative to the event time of the main clause, not the speaker's present:

mi pu djuno le du'u do ba klama I knew [past] that you would go [future relative to that past time].

This parallels how English uses "would" in reported speech. The tense system is consistent and compositional.

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Motion Tenses: mo'i + FAhA#

The particle mo'i marks that the event involves motion in a direction, rather than just location. Combine it with a FAhA direction particle:

mi mo'i ca'u cadzu I walk [moving forward]. (the walking involves forward movement)

le gerku mo'i ri'u bajra The dog runs to the right.

le vinji mo'i ga'u klama The airplane comes [moving upward]. (taking off)

Without mo'i, a direction particle just says where the event is:

le nanmu ca'u batci le gerku = The man bites the dog in front of me. (location) le nanmu mo'i ca'u batci le gerku = The man, moving forward, bites the dog. (motion)

mo'i can combine with time and distance tenses as usual:

mi pu mo'i fa'a le zarci klama I went [past] moving toward the store. (I headed toward the store)

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Interval Boundaries: ga'o and ke'i#

When you specify a time or space interval, you can mark whether the endpoints are included or excluded — like closed vs. open intervals in mathematics:

These appear right before or after interval words to mark which end they apply to:

mi cadzu ga'o le zarci ke'i le briju I walk from the store (inclusive) to the office (exclusive). = I leave from the store (starting point counts) and stop just before the office.

mi sipna ze'u ga'o le nu co'a nicte ke'i le nu co'a donri I sleep from when night begins (inclusive) to when day begins (exclusive).

In practice, the closed/open distinction is mostly relevant in precise mathematical or scheduling contexts, but it mirrors standard mathematical notation and is grammatically available for all interval expressions.

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Rhythm and Habit: TAhE#

The TAhE particles express whether an event happens regularly, continuously, habitually, or at some other rhythmic pattern:

mi ta'e citka lo plise I habitually eat apples. (it's my habit)

le mlatu na'o sipna Cats typically sleep. (it's normal for cats)

le pulce ru'i cpana le rokci The dust continuously lies on the rock.

mi di'i viska le solri I regularly see the sun. (at predictable intervals — every morning)

TAhE particles can combine with time tenses:

mi pu ta'e citka lo plise I used to habitually eat apples. (past habit)

mi ba di'i klama le zarci I will regularly go to the store.

The difference between ta'e and di'i:

• ta'e = habitually (general tendency, not necessarily at fixed intervals)
• di'i = periodically (at predictable, regular intervals — like every Tuesday)

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Quick Reference#

Temporal directions:

Aspect:

Space distances: vi (near), va (medium), vu (far)

Space intervals: ve'i (small area), ve'a (medium), ve'u (large)

Time intervals: ze'i (briefly), ze'a (a while), ze'u (long time)

Motion: mo'i + FAhA direction = moving-in-that-direction

Interval boundaries: ga'o (closed/inclusive), ke'i (open/exclusive)

Rhythm/habit (TAhE): ta'e (habitual), na'o (typical), ru'i (continuous), di'i (periodic)

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CAhA: Actuality, Potentiality, and Capability#

CLL chapter 10 covers a selma'o called CAhA that lets you distinguish not just when something happens but whether it could happen at all:

le karce ca'a klama le zarci The car actually goes to the store. (it's a fact right now)

le karce ka'e klama le zarci The car is capable of going to the store. (in principle — whether or not it does)

mi nu'o vofli I can fly but never have. (untried — I have the theoretical ability but no evidence)

mi pu'i vofli I have actually flown. (demonstrated capability — the proof is in the past event)

ca'a vs. bare tenses: a bare bridi without tense is tenseless (true at some time); ca'a asserts the present fact explicitly. In logical argument, ca'a is the "actualization" operator.

ka'e is especially useful for capabilities of artifacts, animals, and people:

le gerku ka'e batci A dog is able to bite. (it's within their nature)

le verba nu'o cadzu The child can walk but hasn't yet.

Note on universal statements: Lojban tenseless bridi describe what is universally true of a kind, not what is happening now. So ro datka cu flulimna ("all ducks float-swim") is considered true even of sleeping ducks, because it describes their nature. Adding a tense marker — ro datka ca flulimna — still doesn't fully assert current activity; it only narrows the time. For an unambiguous "all ducks are right now actually swimming" you need ca'a: ro datka ca ca'a flulimna.

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VIhA: Dimensionality of Events#

Events can be point-like, linear, areal, or volumetric. The VIhA particles tag this:

mi vi'i klama le bisli I travel along the ice in a line. (linear path)

le bredi cu vi'a cpana le foldi The seed covers the field (as a surface).

le djacu cu vi'u nenri le botpi The water fills the bottle (volumetrically).

VIhA is used mainly in precise spatial descriptions; for everyday speech the bare VA distance particles are usually enough.

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Story Time: Tenses Relative to Narrative Point#

In narrating events, you often set a story-time reference point and then describe other events relative to it. Lojban handles this explicitly with ki:

ki — "sticky tense" bookmark

Attaches to a tense to make it the persistent reference point for subsequent bridi.

puki mi klama le zarci .i le zarci cu barda [Setting: past.] I go to the store. The store is big. (both past)

With ki appended to a tense particle, all subsequent bridi without an explicit tense use that reference:

puki = set "past" as the current reference point baki = set "future" as the reference caki = reset to "present" (speaker's now)

This is how Lojban fiction works: set puki once, and everything that follows is understood as past until reset:

puki la .teris. klama le tcadu .i ri melbi .i la .teris. facki lo cukta [Past:] Terry goes to the city. It is beautiful. Terry finds a book.

All three sentences are past without repeating pu each time.

Without ki, every bridi resets to tenseless (ambiguous time). With ki, you establish a narrative time and stay there.

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Compound Spatial Tenses#

Spatial tense particles can be chained to describe a multi-step imaginary journey through space. Each step adds a direction (FAhA) optionally followed by a distance (VA):

le nanmu ga'u zu'a batci le gerku The man [up] [left] bites the dog. To the left of a place above me, the man bites the dog.

The journey proceeds left to right: first move upward from the speaker, then move left from there. The English gloss reverses the order (innermost step first).

You can attach a distance to each direction separately:

le nanmu zu'avi ga'u vu batci le gerku The man [left-short] [up-long] bites the dog. Far above a place slightly to my left, the man bites the dog.

A distance without a following direction says how far away the event is without specifying direction:

le nanmu vi zu'a batci le gerku The man [short-distance] [left] bites the dog. Left of a place near me, the man bites the dog.

Any number of direction+distance steps may be stacked. In practice, one or two steps are most common.

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Interval Sizes: VEhA and ZEhA#

By default, a tense just says when something happens — it says nothing about how long it takes. The cmavo of VEhA (space) and ZEhA (time) specify the size of the interval over which the event occurs.

These are relative to context — "short" for a geological event is different from "short" for a sentence.

le verba ze'a cadzu le bisli The child [medium-time-interval] walks on the ice. For a medium amount of time, the child walks on the ice.

ZEhA as a sumti tcita (interval specified by reference to an event):

loi snime cu carvi ca le ze'u dunra Snow falls during the long winter. (the winter is long; the snow falls in it)

Here le ze'u dunra is the sumti of the tense tag ca — the event of snow falling is located within the interval described as "the long winter."

le verba ve'i cadzu le bisli The child [small-space-interval] walks on the ice. The child walks on the ice in a small area.

Intervals combine with directions and distances. The interval always comes after the distance/direction:

le verba pu ze'a cadzu le bisli The child [past] [medium-interval] walks on the ice. For a medium time in the past, the child walked on the ice.

Orienting the interval#

By adding a PU or FAhA cmavo after the ZEhA (or VEhA), you specify where the reference point falls relative to the interval:

mi ca ze'ica cusku dei I [present] [short-interval-present] say this. I am saying this sentence now. (the interval straddles the present moment)

mi ca ze'ipu cusku dei I [present] [short-interval-past] say this. I have just been saying this sentence. (interval extends from the past to now)

mi pu ze'aba citka le mi sanmi I [past] [medium-interval-future] eat my meal. For a medium time afterward [from that past moment], I ate my meal.

Without the trailing PU/FAhA, the relationship between reference point and interval is unspecified.

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Space Interval Modifier: FEhE#

The ZAhO aspect particles (co'a, ca'o, co'u, mo'u, za'o) normally describe the phase of an event in time. The cmavo fe'e (selma'o FEhE) is a flag that transfers the ZAhO interpretation to space — meaning "apply this event-contour notion to space, not time."

ko vi'i fe'e di'i sombo le gurni You [1-dimensional] [space:] [regularly] sow the grain. Sow the grain evenly in a line!

mi fe'e ciroi tervecnu lo selsalta I [space: three-places] buy salad ingredients. I buy salad ingredients at three separate locations.

The fe'e prefix can also be used with ZAhO:

tu ve'abe'a fe'e co'a rokci That [medium-space-interval-north] [space:] [start-of] is-a-rock. That is the beginning-edge of a rock extending northward from me.

Here co'a (beginning of) is applied to the spatial extent of the rock rather than to time — the southern face is the "beginning" because the interval extends northward.

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Story Time#

In ordinary Lojban, a tenseless bridi has no implied temporal relationship to other bridi. But in narrative — a story, a report, a sequence of events — speakers use a different convention called story time.

In story time:

• Each new tenseless sentence is understood to occur after the previous one.
• A sticky tense set with ki establishes the narrative starting point.
• An explicit tense in a sentence is interpreted relative to the current story time, not the speaker's present.
• After a flashback (a sentence with explicit tense reaching back in time), story time returns to where it was before the flashback.

Example mini-story:

pu zu ki ku — [long ago, sticky:]

This sets the story to "long ago." From here, all tenseless sentences are understood as long ago, advancing forward in time.

.i ko'a citka loi kanba rectu — She was eating goat's meat. .i ko'a pu jukpa ri le mudyfagri — (Flashback) She had cooked it over a wood fire. .i lei rectu cu zanglare — The meat was pleasantly warm. (story time resumes after the flashback)

The flashback with pu goes before the eating event but does not advance story time. After the flashback sentence, story time picks up where the eating left off.

Story time is how Lojban narratives are written naturally — set a time with ki, then let sentences flow without repeating the tense. Use explicit tenses only for flashbacks (pu) or flash-forwards (ba).

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Tenses in Subordinate Bridi#

When a bridi is embedded inside another (as an abstraction, relative clause, or description), the inner tense is interpreted relative to the outer tense, not relative to the speaker's present.

English works differently: English always measures tense from the speaker's present. Lojban follows the convention of Russian and Esperanto — relative tense.

la djan. ca cusku le se du'u la jord. ca klama le zarci John [present] says the-statement-that George [present] goes to the market. John says that George is (right now, while John speaks) going to the market.

la djan. pu cusku le se du'u la jord. ca klama le zarci John [past] said the-statement-that George [present] goes to the market. John said that George was (at the time of John's saying) going to the market.

In the second sentence, ca inside the subordinate bridi means "simultaneously with John's speaking (in the past)" — not "simultaneously with right now." This is the key difference from English.

la djan. pu cusku le se du'u la jord. pu klama le zarci John [past] said the-statement-that George [past] went to the market. John said that George had gone to the market (before the moment of speaking).

nau: Override to Speaker's Present#

When you are deep inside nested subordinate bridi but want to refer to the speaker's actual present moment (not the relativized one), use nau (selma'o CUhE):

la djan. pu cusku le se du'u nau mi sipna John [past] said the-statement-that [now-actually] I am asleep. John said that (as I am telling you this) I am asleep.

nau escapes all the relative tense nesting and points directly to the moment of utterance. It cannot be combined with other tense particles (except through logical connection). It has no effect on sticky tenses.

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Tense Negation#

Tense particles can be negated with nai to produce roughly the opposite meaning:

mi pu klama le zarci — I went to the store. mi punai klama le zarci — I didn't go to the store [in the past]. (equivalent to na in many contexts, but specifically negates the tense)

More usefully, nai on ZAhO aspect particles means the event is not at that stage:

mi ca'onai citka — I am not in the middle of eating.

Tense negation contrasts with bridi negation (na): mi na pu klama negates the whole claim (it is not the case that I went), while mi punai klama specifically says "at past time, not going" — a subtle but sometimes important distinction.

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Vague intervals — pu is not English “finished past”#

If you do not give a ZEhA interval size, Lojban leaves the interval vague. mi pu klama le zarci puts some part of the going in the speaker’s past — it does not promise the whole trip ended before “now” (English went often implies completion). Likewise:

le tricu ba crino The tree will be green — does not exclude the tree being green already; the stretch of “being green” may have begun.

To force completion, phases, or duration, use ZAhO (co'i, co'u, …), ze'a, or more specific wording — not pu alone.

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Tense tagging a sumti (sumti tcita)#

Besides floating tenses (ku) or pre-selbri position, a tense can sit immediately before a sumti to relate the main bridi to that sumti in time or space.

Time:

mi klama le zarci ca le nu do klama I go to the store at the same time as your going.

mi klama le zarci pu le nu do pu klama le zdani I go to the market in the past of your (then) going to the house — often glossed as *I had gone to the market before you went to the house._

Space:

le ratcu cu citka le cirla vi le panka The rat eats the cheese in the vicinity of the park.

jai + tense promotes the tagged place to x₁ of a new selbri; the old x₁ can reappear as fai (Chapter 4):

le panka cu jai vi citka le cirla fai le ratcu The park is the locus of the rat’s eating the cheese.

mi djuno fi le jai ca morsi be fai la .djan. I know about the time when John is dead — the time of John’s death.

Temporal ZAhO and roi can also tag sumti; see CLL-style advanced examples when you need phase-of-process relative to le nu.

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Sub-events: stacked contours and counts#

You can stack aspect and repetition without a connective:

la .djorj. ca'o co'a ciska George continues to begin to write. (each cmavo narrows the phase)

mi reroi ca'o xaroi darxi le damri On two occasions, I keep hitting the drum six times each time.

The cross-product connective pi'u between counts (CLL’s “twelve shots” from 2×6) exists but is rare; treat it as advanced.

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Tenses vs modals#

Syntax: Tenses and modals occupy the same structural “slots”: before the selbri, with ku, as sumti tcita, in connections, and with jai. Semantics: tenses answer when / where the bridi sits; modals add why / how / in what language / with what tool — roles beyond the gismu’s built-in places. A single bridi can carry both: mi pu klama le zarci mu'i le nu mi djica — past going, motivated by wanting.

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Beyond “short / medium / long” distances#

ZI and VA only give three coarse sizes. For exact offsets or durations, Lojban uses mekso (numbers), nu'i … nu'u termsets after a tense tag, and related machinery (Chapter 14, Chapter 16, Chapter 18). Everyday prose rarely needs this; skip until you write precise schedules or physics.

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Full FAhA direction inventory (reference)#

The quick table earlier lists common directions. The full set includes (static “where” / mo'i “moving” uses the same cmavo):

Compass and viewer-relative directions mix; pick one frame and stay consistent in a passage.

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Finally: mixed tense practice (capstone)#

Use this block to integrate everything from the chapter: read, name the pieces, produce.

1 — Identify components
For each bridi, say which selma’o you see (e.g. PU, ZI, ZEhA, FAhA, VA, ZAhO, ROI …) and in what order they attach:

mi puze'a klama le zarci

le verba cu vi ne'i le zdani co'u sipna

la .djan. reroi pu klama le briju

2 — Paraphrase
Express roughly: “I will go to the store soon” vs “I will go to the store a long time from now” using ba + ZI (and ku only if you need to front the tense).

3 — Connective question (ties to Chapter 8 and Chapter 16):

la .artr. pu je'i ba nolraitru

What does je'i ask for? What kinds of answer are grammatical?

4 — Optional stretch (harder)
Skip these until the rest of the chapter feels easy; they mix sticky tense, double aspect, and “vague future” readings.

• Sticky narrative: puki is pu + ki — the tense sticks for later bridi. What tense is the second sentence?

  mi puki klama le zarci .i mi klama le zdani I [past-sticky] went to the market. I go to the house.

• Stacked contours: Name both ZAhO pieces and the overall story (start vs stop vs ongoing):

  mi ca'o co'u bajra

• Vague interval (trap): Does ba always mean “will / going to”? Paraphrase the following without adding a false English “will”:

  le tricu ba crino

For bridi negation vs tense order (na ku), see Chapter 13.

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Summary#

• Tense is always optional; omit it when context is clear
• pu / ca / ba = past / present / future
• zi / za / zu = short / medium / long time distance (combined: puzi, bazu, etc.)
• ze'i / ze'a / ze'u = interval size (how long the event lasts)
• Spatial tenses use vi/va/vu (distance) and FAhA particles (direction)
• mo'i + FAhA = motion tense (the event involves movement in that direction)
• ga'o = closed endpoint (inclusive); ke'i = open endpoint (exclusive)
• TAhE rhythm: ta'e (habit), na'o (typical), ru'i (continuous), di'i (periodic)
• Time comes before space when both are given
• Aspect particles (co'a, ca'o, co'i, co'u, mo'u, za'o) describe the shape of events
• Use ku to move a tense out of default position for emphasis
• CAhA: ca'a (actually), ka'e (capable), nu'o (untried), pu'i (demonstrated)
• VIhA: vi'i (line), vi'a (surface), vi'u (volume), vi'e (space-time)
• ki: sticky-tense bookmark — sets reference for subsequent bridi; caki resets to present

Compound spatial tenses:

• Multiple FAhA cmavo stack (inner first): zu'avi'i = a short line forward
• VEhA (spatial interval): ve'i = small area, ve'a = medium, ve'u = large
• ZEhA (temporal interval): ze'i = short, ze'a = medium, ze'u = long
• Both stack on direction: puze'a = for a medium past duration

FEhE — space interval modifier:

• Placed after a spatial tense to specify the shape of the space interval
• vi FEhE + FAhA = the space around the event is in direction FAhA

Story time and nau:

• ki (sticky tense) advances the narrative reference time implicitly in stories
• Tenseless sentences in a narrative pick up the sticky tense from prior context
• nau overrides all tense context — forces interpretation relative to speaker's actual now
• puki = set story-past reference; subsequent sentences without tense are past relative to it

Finally (capstone): mixed tense drills + je'i — see Finally: mixed tense practice above (including optional stretch)

Chapter 10. Modals & Causality#

What Are Modals?#

Every numbered place in a gismu's place structure was chosen during language design. But real speech sometimes needs to attach extra information beyond those fixed slots — things like with what tool, because of what, for what purpose, in what language, and so on.

Lojban handles this with modal tags (sumti tcita): particles that introduce an extra argument with a specific semantic role. They come in two forms:

1. fi'o + selbri — build a custom modal from any relation word
2. BAI cmavo — pre-built shorthand modals for common roles

Both work the same way: tag goes directly before the argument that fills that role.

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fi'o: Custom Modal Tags#

fi'o followed by a selbri creates a modal meaning "filling x₁ of [selbri]":

mi viska do fi'o kanla le zunle I see you [x₁-of-eye: the-left-thing] → I see you with my left eye.

Here fi'o kanla means "in the role of x₁ of kanla (eye)" — so le zunle fills that role. The x₁ of kanla is the eye, so this says the left thing is the eye used.

Since we often want a place other than x₁, combine fi'o with SE conversion:

mi viska do fi'o se pilno le zunle kanla I see you [x₁-of-se-pilno: the-left-eye] → I see you using my left eye.

se pilno = "is used by x₂ to …" so x₁ of se pilno is the tool. le zunle kanla fills that tool slot.

The terminator fe'u closes a fi'o modal (usually elidable):

mi klama le zarci fi'o se pilno le karce fe'u I go to the store [by-means-of: the car] → I go to the store by car.

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BAI: Pre-built Modal Shorthand#

Because certain modal roles are needed constantly, Lojban provides ready-made BAI cmavo (selma'o BAI). Each is derived from a specific gismu and abbreviates fi'o [that gismu].

Here are the most useful BAI modals:

Causality:

Circumstance:

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Causality in Depth#

English has one word "because" where Lojban has four distinct causal relations:

rinka

x₁ (event) physically causes x₂ (event)

mukti

x₁ (event) is the motive/intention causing x₂ (event)

krinu

x₁ (event/fact) is the justification for x₂

nibli

x₁ (proposition) logically entails x₂

le spati cu banro ri'a le nu do djacu dunda fi le spati The plant grows because you water it. (physical causation)

mi lebna le cukta mu'i le nu mi tadni I take the book because [my motive is] studying. (intentional motivation)

la .sokrates. morsi binxo ni'i le nu ro remna cu morsi Socrates died because [logically] all humans die. (logical entailment)

la .djan. cpacu le pamoi se jinga ki'u le nu le skina cu melbi John gets first prize because [justification:] the film is beautiful.

These distinctions eliminate a vast amount of ambiguity inherent in English "because", "since", and "therefore".

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Modal Sentence Connection#

A modal tag can also connect two full sentences — saying the second happened because of (or caused, or was justified by) the first. Use .i + modal + bo in afterthought:

le spati cu banro .iri'abo do djacu dunda fi le spati The plant grows; [because] you water it.

Or use seri'a (= with effect) to connect in the other direction:

do djacu dunda fi le spati .iseri'abo le spati cu banro You water the plant; [therefore] it grows.

The -bo prevents the modal from grabbing the next sumti as its argument; without bo, .iri'a do would mean "because of you" (taking do as its sumti).

Forethought modal connection (signal before first bridi):

ri'a gi do djacu dunda fi le spati gi le spati cu banro Because you water the plant, it grows. (ri'a ... gi ... gi)

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Common BAI Examples#

mi tavla bau la .lojban. I speak in Lojban. (bau = in language)

mi cadzu sepi'o le tuple I walk using my legs. (sepi'o = with tool = legs)

do klama zu'e le nu do citka You go for the purpose of eating. (zu'e = for purpose)

mi viska do gau le drata I see you [done-by: another person] → someone else causes me to see you / someone shows you to me.

mi tavla do ca'i le turni I speak to you by authority of the governor.

ko tavla mi bai [ku] Talk to me under compulsion! → Talk to me whether you want to or not!

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Tense and Modal Together#

Modal tags and tense tags occupy the same structural position before the selbri. They can co-occur in any order:

mi pu klama le zarci zu'e le nu mi citka I went to the store for the purpose of eating.

mi ba cadzu sepi'o le karce ri'a le nu le karce cu spofu I will walk by means of (no, wait) — because the car is broken.

(Rethought: in practice you'd pick one modal per tag slot, or separate into multiple bridi.)

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Modal Selbri (BAI + ku)#

A BAI particle followed by ku (with no following sumti) becomes a standalone modal without a specific argument, meaning "in-the-relevant-way":

mi tavla bau la .lojban. bai ku I speak in Lojban under compulsion (bai = under compulsion, but who's compelling is unspecified)

mi cadzu sepi'o ku I walk using [some unspecified tool]

This lets you signal the type of relationship without specifying the filler — useful when the filler is obvious from context.

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Key BAI Quick Reference#

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Modal Negation#

Modals can be negated with nai after the BAI particle to assert the absence of that relation:

mi klama le zarci mu'inai I go to the store without motivation. (or: the motivation does not apply to my going)

mi klama le zarci ki'unai le nu mi djica I go to the store, not for the reason of wanting to.

This is modal negation — it negates the role the sumti plays, not the whole bridi. Compare:

• mi na klama le zarci mu'i le nu mi djica = It's not the case that I go to the store due to wanting to. (bridi negation — whole claim is false)
• mi klama le zarci mu'inai le nu mi djica = I do go, but not because of wanting to. (modal negation — the causal link is denied)

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Sticky Modals: ki with BAI#

Just as ki makes tenses sticky (persistent across bridi), it can also make modal tags sticky. Append ki to any BAI to set it as the default modal for subsequent bridi:

bau la .lojban. ki mi tavla .i mi cusku .i mi pensi [In Lojban (set):] I talk. I say. I think. (all three understood as happening in Lojban)

mu'i le nu mi prami do ki mi klama le zarci .i mi dunda le cukta [Motivated by loving you (set):] I go to the store. I give the book. (both actions share the same motivation)

Reset a sticky modal with the bare BAI + ki with no argument (or start a new ki binding):

do'eki = "unspecified relation (set)" — vague reset bau ku ki = reset to no specified language

Sticky modals are especially useful in narrative when a single circumstance or cause applies to a whole sequence of events.

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BAI reference (official selma'o)#

Every BAI cmavo is tied to a gismu’s place (see the dictionary gloss: “gismu modal, _n_th place …”). The list below matches cmavo.tsv / gismu.tsv in this repo — not every spatial direction (ri'u, zu'a, …) is a BAI; those are FAhA, used as tense tags, not modal fi'o-style tags.

Causality, result, and purpose

Agency, instrument, beneficiary

Comparison and superlative

Language, culture, category, conditions

Other common ones

Not BAI: kau (indirect-question marker, UI), zu'u (discursive “on the one hand …”, UI), ri'u (FAhA direction).

For the complete alphabetical list, use jbovlaste or another official cmavo index; this site’s dictionary data may also expose BAI entries programmatically.

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Modal Comparatives: mau and me'a#

Two BAI cmavo are especially useful for comparisons: mau (from zmadu, more than) and me'a (from mleca, less than). Their place structures:

Because what you typically want to specify is the basis for comparison (x₂ — the thing being compared to), these BAI are usually used with se conversion:

• semau — "more than [comparison basis]" (x₂ of zmadu)
• seme'a — "less than [comparison basis]" (x₂ of mleca)

la frank. nelci la betis. semau la meiris. Frank likes Betty more than [he likes] Mary.

The semau la meiris. gives the basis: Frank's liking for Mary is what Betty's is being compared to.

la frank. nelci la meiris. seme'a la betis. Frank likes Mary less than [he likes] Betty.

Same information, different emphasis.

Modal Relative Phrases: pe/ne + modal#

When a comparison applies specifically to a sumti rather than to the whole bridi, attach the modal using a relative phrase — pe (restrictive) or ne (incidental):

la frank. nelci la betis. ne semau la meiris. Frank likes Betty, who he likes more than Mary.

Without ne, semau la meiris. would attach to the whole bridi (comparing the event of liking to Mary, which is nonsense). The ne binds the comparative to la betis. specifically.

la frank. nelci la meiris. ne seme'a la betis. Frank likes Mary, whom he likes less than Betty.

This pattern works with many other BAI. Some common ones used with relative phrases:

Pure comparison (without asserting the main bridi):

le ni la frank. cu nelci la betis. cu zmadu le ni la frank. cu nelci la meiris. The degree to which Frank likes Betty exceeds the degree to which he likes Mary.

This asserts only the comparison — it doesn't claim Frank actually likes either of them.

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Connecting Modals Logically#

When two bridi differ only in their modal tags, Lojban lets you reduce them to a single bridi with a connected modal. The connection works like any other logical connective:

mi klama le zarci ri'a le nu lo gerku cu batci mi I go to the store because a dog bit me.

mi klama le zarci ki'u le nu mi djica I go to the store because (justified by) I want to.

To say both simultaneously:

mi klama le zarci ri'aje ki'u le nu … I go to the store because of [physical cause AND justified reason] …

Or in afterthought:

mi klama le zarci ri'a le nu lo gerku cu batci mi .i ji'a ki'u le nu mi djica

When a single event is both the physical cause and the motivation:

mi klama le zarci ri'a ce'e ki'u le nu lo gerku cu batci mi I go to the store [physically-because AND justification-because] a dog bit me.

The ce'e creates a termset: both modal tags apply to the same sumti simultaneously.

Logical connective + modal together: You can assert both that two bridi are connected by logic (.ije = and) and by a modal relation — the modal is glued after the logical connective, before bo:

mi nelci do .ije mi nelci la .djim. I like you, and I like Jim.

mi nelci do .iki'ubo mi nelci la .djim. I like you; justified by [the fact that] I like Jim.

mi nelci do .ijeki'ubo mi nelci la .djim. I like you and, with that justified by [the fact that], I like Jim. — both the .ije and the ki'u link apply.

When the two bridi differ only in one sumti, you can compress:

mi nelci do .eki'ubo la .djim. I like you and/because Jim. (sumti-level .e + ki'u + bo)

Forethought connectives stay either logical or modal — not mixed in one gi chain. See Chapter 8 for connective details.

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seBAI: General Conversion Rule#

Any BAI cmavo can be prefixed with se (or te, ve, xe) to shift which place of the source gismu is being filled:

• mau fills x₁ of zmadu ("exceeded by …")
• semau fills x₂ of zmadu ("more than …" — the comparison basis)
• temau fills x₃ of zmadu ("in property of …")
• vemau fills x₄ of zmadu ("by amount …")

This works for any BAI, not just comparatives:

The conversion mirrors SE on selbri: seBAI fills "the thing that [source gismu]'s x₂ is" relative to the BAI's argument.

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Irregular BAI shapes#

Most BAI cmavo are regular CV’V pieces cut from a gismu’s first consonant + two vowels. The 65 BAI cmavo include 36 regular CV’V forms and a set of irregular ones. The irregularities fall into four categories:

1. CVV form (monosyllables — no apostrophe):

2. Uses the 2nd consonant of the gismu (collision avoidance):

3. Based on a lujvo, not a bare gismu:

4. Irregular 2nd vowel:

do’e stands alone: it is the generic/vague modal not derived from any specific gismu. Use it when no other BAI fits.

You do not need to memorize all irregularities — dictionary entries list each BAI’s source. This table explains why mau is not zmu and why dictionaries look inconsistent at first glance.

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jai — modal conversion (full treatment in Chapter 4)#

jai turns the modal’s sumti into x₁ of the bridi, and shoves the old x₁ into fai when it still needs a slot. Chapter 4 has the full pattern (jai gau, se jai, etc.). One classic bau example:

la .lojban. jai bau cusku fai mi Lojban is the language of my expressing [something]. (la .lojban. = modal “language” place as x₁; mi = old speaker in fai.)

jai also has a non-modal abstraction use (sumti raising); Chapter 12 ties that together.

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Tense Stacking: The Imaginary Journey#

When multiple tense elements appear before a selbri, they are not redundant — each one extends the reference point established by the previous one. Think of it as taking an imaginary journey:

1. Start at the "default" reference point (usually the speech moment, nau).
2. The first tense element moves you to a new reference point.
3. The second tense element moves you again from that new point.
4. The selbri's event happens at wherever you've arrived.

mi pu ba klama le zarci I [past] [then future] go to the store.

Step 1: move backward to some past moment (pu). Step 2: from that past moment, move forward (ba). The result: I will go to the store at some point after that past moment — possibly still in the past relative to now, or possibly in the future.

This explains why pu ba ≠ ba and ≠ pu: it means "at some point after X, where X was in the past."

mi ba pu klama le zarci I [future] [then past] go to the store.

Step 1: move forward to some future point (ba). Step 2: from that future point, move backward (pu). The result: before that future moment, I go to the store — this describes something that will have already happened by a certain future time.

The imaginary journey applies equally to direction tenses (vi/va/vu) and event contours (co'a, ca'o, etc.), allowing very precise temporal-spatial descriptions.

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Summary#

• fi'o + selbri creates a custom modal tag from any relation word
• BAI cmavo are predefined shorthand modals for common semantic roles
• Four causal BAI: ri'a (physical), mu'i (motivation), ki'u (justification), ni'i (logical)
• Modal sentence connection: .iri'abo (because-of), .iseri'abo (therefore)
• Forethought modal: ri'a gi … gi (because [A], [B])
• BAI + ku = modal without specified argument (role implicit from context)
• BAI + nai = modal negation (that role does not apply)
• BAI + ki = sticky modal (persists across subsequent bridi until reset)

Modal comparatives:

• semau = more than [basis] (x₂ of zmadu); seme'a = less than [basis] (x₂ of mleca)
• Attach to bridi-level: la frank. nelci la betis. semau la meiris. = Frank likes Betty more than Mary
• Attach to sumti via ne/pe: la betis. ne semau la meiris. = Betty (the one he likes more than Mary)
• Without ne, a comparative modal attaches to the whole bridi — often nonsensical
• Pure comparison (no main-bridi assertion): le ni … cu zmadu le ni …

Connected modals:

• Modals can be joined by jeks: ri'aje ki'u = both physically-because and justified-because
• ce'e in a termset: both modal tags apply to the same sumti simultaneously
• Mixed logical + modal: .ijeki'ubo, .eki'ubo (logical connective + ki'u + bo)

Other:

• Many BAI are regular CV'V; mau, kai, rai, tai, do'e are common exceptions — see Irregular BAI shapes above
• jai + modal: Chapter 4; abstraction jai without modal: Chapter 12

Chapter 11. Relative Clauses & Possession#

What Is a Relative Clause?#

A relative clause is a mini-bridi attached to a sumti that says more about it. In English: "the dog that bit me", "the store I went to", "the person who is singing".

What are you pointing at?#

ti, ta, and tu only say how far away something is — not what part of the thing you mean. Point at someone’s face and say:

ti cu barda This is big.

Is ti the whole person, the nose, or a tiny patch of skin? Relative clauses exist so you can narrow the referent with a full mini-bridi:

ti poi ke'a prenu cu barda This [thing], which is a person, is big.

ti poi ke'a nazbi cu barda This [thing], which is a nose, is big.

ti poi ke'a nazbi bo kapkevna cu barda These [things], which are nose-pores, are big. (kapkevna ≈ skin-hole / pore; bo groups the tanru clearly.)

Same pointing gesture — three different poi clauses, three different meanings. The rest of this chapter explains how to build and combine these clauses; pe / po / po'e shortcuts come a bit later.

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In Lojban, relative clauses attach to sumti using two particles:

poi

restrictive relative clause — narrows down which referent is meant

noi

incidental relative clause — adds parenthetical information about an already-identified referent

The relative clause is closed by the elidable terminator ku'o. Inside the clause, ke'a stands for the sumti the clause is attached to.

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poi: Restrictive Relative Clauses#

poi introduces a clause that restricts the referent — you need it to know which thing is meant:

le gerku poi blabi cu barda The dog that is white is big.

Without "that is white", you wouldn't know which dog. The poi clause is essential to identification.

ke'a marks the relativized sumti's position inside the clause:

ti poi ke'a prenu cu barda This thing such that it is a person is big. → This person is big.

When ke'a falls in x₁, it can be omitted (the default):

le gerku poi blabi cu barda = le gerku poi ke'a blabi cu barda The dog that is-white is big.

ke'a can fill any slot in the clause:

tu poi le mlatu pu lacpu ke'a cu ratcu That thing which the cat dragged is a rat.

Here ke'a is in x₂ of lacpu (the dragged object), not x₁.

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noi: Incidental Relative Clauses#

noi adds parenthetical information. The referent is already identified; the clause just elaborates:

le gerku noi blabi cu barda The dog, which is white, is big.

The comma-equivalent is the key difference from poi. In noi, the clause doesn't change which dog — you already know. It just adds "and by the way, it's white."

mi noi pajni cu zvati I, a judge, am present. (who I am is already known; "judge" is extra info)

le mi karce noi blabi cu spofu My car, which is white, is broken. (I have one car; its whiteness is incidental)

vs.

le mi karce poi blabi cu spofu My car that is white is broken. (I have multiple cars; we need "white" to pick the right one)

The distinction maps onto English punctuation: poi = no commas (restrictive), noi = with commas (incidental).

Restrictive clause vs. tanru: Often you can fold the property into the selbri instead of using poi:

xu do viska le mi blabi karce Do you see my white car?

That is close in spirit to le mi karce poi blabi, but a tanru like blabi karce can be vague (white things about the car, carriers of white things, etc.). A poi clause can only mean “the car is white” in the sense of the bridi inside poi. For precise identification, prefer poi when it matters.

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Multiple Relative Clauses: zi'e#

To attach more than one relative clause to the same sumti, join them with zi'e:

le gerku poi blabi zi'e poi batci le nanmu cu klama The dog that is white and that bites the man goes.

le gerku poi blabi zi'e noi le mi pendo cu ponse cu batci The dog that is white, which my friend owns, bites [someone].

You can mix poi and noi with zi'e.

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Possession: pe, po, po'e, po'u#

Rather than a full relative clause, Lojban has relative phrase shortcuts using GOI cmavo. These are a single particle followed by one sumti:

pe — loose association ("associated with")

Like saying "of" or "belonging to" in a general, contextual sense.

le stizu pe mi cu blanu The chair of mine is blue. (the one I'm currently sitting on, or loosely associated with)

po — specific possession (alienable)

A more permanent connection, typically ownership.

le stizu po mi cu xunre My chair is red. (the one I own)

po'e — intrinsic/inalienable possession

Cannot be separated from the possessor without changing them.

le birka po'e mi cu spofu My arm is broken. (it's intrinsically mine — body part)

po'u — identity

This isn't possession but identification: "which is [the same thing as]".

le gerku po'u le mi pendo cu cinba mi The dog, which is my friend, kisses me. (dog = my friend, same entity)

le tcadu po'u la .nu,IORK. cu barda The city which is New York is big. (disambiguates which city)

ne — incidental loose association (like noi version of pe)

le blabi gerku ne mi cu batci do The white dog, which is mine, bites you.

no'u — incidental identity

le nanmu no'u la .djim. cu terpemci The man, Jim, is a poet.

A GOI phrase is one sumti after the marker; the phrase ends with an elidable ge'u (almost always dropped) if something else follows that could be confused with more of the phrase.

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Phrase or full clause? (GOI and poi)#

Many GOI phrases say the same thing as a longer poi clause — the phrase is just shorter when the relation is a simple “about / associated with”:

le stizu pe mi cu blanu My chair is blue (loose association).

le stizu poi ke'a srana mi cu blanu The chair that pertains to me is blue. — same idea, with srana (x₁ pertains to x₂).

po is stronger than pe (“specifically associated” — often possession): le stizu po mi ≈ le stizu poi ke'a se steci srana mi in spirit. You do not need to memorize the long form; use it when you are unsure what pe vs po implies.

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Possession vs. Place Structures#

Many gismu already have an "owner" or "body" place built in. For body parts, you can use the place structure directly:

le birka be mi cu spofu = le birka po'e mi cu spofu My arm is broken. (birka x₂ = the body it belongs to)

When the gismu has the right slot, this is more concise than using po'e. But po'e is more general — it works even when there's no dedicated place.

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be: Filling Inner Places of a Description Selbri#

When you build a description with le, you can fill the selbri's non-x₁ places inside the description using be … bei … be'o:

be

fills x₂ of the selbri

bei

fills x₃, x₄, etc.

be'o

closes the be construction

le dunda be le rozgu bei mi The giver of the rose to me (dunda: x₁ gives x₂ to x₃; be=x₂=le rozgu, bei=x₃=mi)

le klama be la bastn. bei la .atlantas. The goer to Boston from Atlanta

This is how you build rich, place-filled descriptions without breaking them into separate sentences.

le birka be mi = the arm of my body (using be to fill x₂ of birka)

Why does be/bei/be'o exist?#

This is a grammar-motivated question. Without be, the parser faces an ambiguity whenever a sumti follows the selbri inside a description:

le mamta mi — is mi filling x₂ of mamta (= my mother)? Or is it a second sumti in the outer bridi?

The answer from the grammar: a bare sumti after a selbri inside a le description is not interpreted as filling the selbri's inner places. It is parsed as another sumti of the outer bridi.

be is the explicit signal that says "this sumti belongs inside the description, filling a numbered place of the selbri":

le mamta be mi = unambiguously "the mother of me" le mamta mi = ambiguous / likely parsed as two separate sumti

The chain continues with bei for each additional inner place:

le dunda be le rozgu bei mi bei la .paris. The giver of the rose to me in Paris (dunda: x₁=giver x₂=thing given x₃=recipient x₄=origin)

be'o closes the chain. It is needed when a relative clause or another structural word immediately follows — without it, the parser might try to absorb the relative clause into the be chain:

le dunda be le rozgu bei mi be'o poi melbi cu zvati The giver of the rose to me who is beautiful is here. (be'o explicitly ends the inner-place filling before poi)

In practice be'o is often omitted when ku or the end of the description makes the boundary clear, but it is required to avoid ambiguity with relative clauses.

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Relative Clauses in Descriptions with be#

You can combine be and relative clauses:

le gerku poi blabi be mi The dog that is white (that belongs to me)

or:

le gerku be mi poi blabi My dog that is white (be mi = x₂ of gerku = my body? No — gerku x₂ is breed, not owner)

The interaction of be and relative clauses requires care: be fills a numbered place, while relative clauses are adjuncts. They combine freely.

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voi: The Speaker-Restrictive Clause#

voi is a variant of poi that creates a "speaker-asserted" restrictive clause, parallel to the le vs lo distinction:

lo prenu poi klama — a person who comes (really is a going-person)

lo prenu voi klama — a person who I call a going-person (speaker's description)

voi is less common but worth knowing.

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vu'o: Relative Clauses Across Complex Sumti#

Normally, a relative clause attaches only to the immediately preceding sumti. But what if your sumti is complex — already carrying a pe phrase or a be chain? vu'o extends the attachment point to span the entire sumti:

le gerku pe mi poi blabi cu barda The dog of mine that is white is big. (poi attaches to "le gerku pe mi" as a whole)

Without vu'o, a relative clause in an ambiguous position might attach to just the innermost piece. With vu'o, you make explicit that the clause modifies the entire complex:

le gerku pe mi vu'o poi blabi cu barda My dog, [as a whole,] which is white, is big.

vu'o is the signal: "the relative clause that follows attaches to everything from the start of this description, not just the last word."

This becomes important with longer chains:

le dunda be le rozgu bei mi vu'o poi melbi cu klama The giver of the rose to me, who is beautiful, comes. (poi melbi modifies the whole description "giver of the rose to me", not just mi)

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Relative Clauses in Vocative Phrases#

When addressing someone with a vocative, you can add a relative clause to describe which person you're calling:

coi ro do poi klama le zarci Hello, all of you who are going to the store!

doi la .djan. poi melbi Hey John who is beautiful! (or: Hey, you beautiful John)

pe'u do poi ponse le karce [Please,] you who own the car.

The relative clause after a vocative works like any other — it restricts (poi) or adds information (noi) about the person being addressed.

Relative Clause Position Effects#

Where you place a relative clause relative to a description can subtly change the meaning:

After a le description — restricts which individuals are meant (most common):

le gerku poi blabi cu barda The dog(s) that are white are big. (poi restricts: only the white dogs)

After a bare lo description — the clause becomes part of the description itself, defining what kind of thing counts:

lo gerku poi blabi cu barda Something that is a white dog is big. (the clause and the selbri together define the type)

Inside a description (before the selbri, after the descriptor) — the clause applies to the entire description-group quantifier, not just the final member:

le poi blabi ku gerku cu barda (Grammatically unusual; normally the clause follows the full noun phrase.)

The safest rule: relative clauses follow their entire sumti. Use vu'o to disambiguate when the sumti is complex.

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Nested Relative Clauses and ke'a Subscripts#

When a relative clause appears inside another relative clause, both use ke'a as the relativized pronoun — but they refer to different sumti. Without disambiguation, this is ambiguous:

le prenu poi prami le gerku poi batci ke'a

Which ke'a — the person or the dog? To disambiguate, subscript ke'a with xi:

le prenu poi ke'a xi pa prami le gerku poi batci ke'a xi re The person₁ who loves the dog₂ that bites [the person₁]

ke'a xi pa refers to the outer relative clause's antecedent (the person); ke'a xi re refers to the inner clause's antecedent (the dog). Alternatively, assign one of the sumti to a ko'a slot before introducing the clause:

le prenu goi ko'a poi prami le gerku poi batci ko'a The person [= ko'a] who loves the dog that bites ko'a

The ko'a approach is clearer in most practical writing.

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Relative Clause Terminators: ku'o vs vau#

Both ku'o and vau can close a poi/noi/voi relative clause:

• ku'o — the dedicated NOI terminator; closes only relative clauses.
• vau — the general bridi terminator; also valid here and one syllable shorter.

In most cases, both are elidable at the end of the relative clause (before the main bridi's selbri or before .i). The case where a terminator must be kept is when the relative clause is followed immediately by another relative clause without zi'e:

le gerku poi blabi ku'o noi barda cu klama The dog, which is white and which (by the way) is big, comes.

Without ku'o, the parser might try to attach noi barda to the wrong level. Using zi'e to join them is usually cleaner:

le gerku poi blabi zi'e noi barda cu klama

---

Summary#

Chapter 12. Abstractions#

The Core Idea#

Lojban lets you take an entire bridi — a whole claim — and treat it as a thing: an event, a property, a proposition, a quantity. This is called abstraction, and it's done by prefixing a bridi with one of the NU particles.

Without abstractions, you can say mi klama le zarci (I go to the store). With abstraction, you can wrap that up and talk about the going:

le nu mi klama le zarci the event of my going to the store

This abstract sumti can now go in any slot of another bridi:

le nu mi klama le zarci cu pluka The event of my going to the store is pleasant.

mi nelci le nu mi klama le zarci I like the event of my going to the store. → I like going to the store.

The bridi inside an abstraction is closed by kei (elidable terminator). When the abstraction ends the sentence or is followed by cu, kei can usually be omitted.

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nu: Events#

nu is the general event abstractor — the most common NU.

nu

x₁ is an event/state described by the bridi

le nu la .teris. cadzu the event of Terry walking

le nu do klama cu ckape The event of you coming is dangerous.

Lojban "events" in this sense can be brief (a kiss) or lifelong (breathing). nu doesn't care — it just packages the bridi as a thing that happened / is happening / will happen.

Four refined event abstractors:

mu'e

point-event — the bridi seen as a single unstructured moment

pu'u

process — structured event with beginning, stages, end

zu'o

activity — repetitive or cyclic event

za'i

state — condition that either holds or doesn't

le mu'e la .djan. catra la .djim. the (point-event) of John killing Jim — seen as instantaneous

le pu'u le latmo balje'a cu porpi the process of the Roman Empire falling apart — structured and extended

mi tatpi ri'a le zu'o mi plipe I'm tired because of the activity of jumping.

le za'i mi jmive cu ckape do The state of my being alive is dangerous to you.

All four can be replaced by bare nu with some loss of precision.

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ka: Properties#

ka abstracts a property — a quality that things can have or lack.

ka

x₁ is the property described by the bridi

Properties are used to fill quality-slots in many gismu:

do cnino mi le ka xunre You are new to me in the quality of being red. → Your redness is new to me.

mi zmadu do le ka clani I exceed you in the property of being tall. → I am taller than you.

ce'u marks the "open slot" of the property — the thing that has the property:

le ka ce'u clani the property of being tall (ce'u = the thing that is tall)

When the open slot is x₁ (default), ce'u can be omitted. But when it's in another position, you need it:

le ka mi prami ce'u the property of being loved by me (ce'u = the thing loved)

le ka ce'u prami mi the property of loving me (ce'u = the lover)

These two properties are very different! The explicit ce'u prevents ambiguity.

Two ce'u = a relationship abstraction (rare but valid):

le ka ce'u prami ce'u the relationship of loving

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du'u: Propositions#

du'u abstracts a proposition — a claim that is either true or false.

du'u

x₁ is the proposition that [bridi]

Use du'u when you want to talk about a claim as a fact (something known, believed, said, etc.):

mi djuno le du'u do klama I know the proposition that you are going. → I know that you are going.

mi jinvi le du'u le mlatu cu melbi I believe the proposition that the cat is beautiful. → I think the cat is beautiful.

la .alis. cusku le du'u mi cadzu Alice says the proposition that I walk. → Alice says that I walk.

du'u vs nu: Use du'u for mental and verbal acts (knowing, believing, saying, claiming). Use nu for physical/experiential events (seeing, hearing, doing, liking in a sensory way):

mi djuno le du'u do klama — I know that you're going. (proposition) mi viska le nu do klama — I see the event of you going. (event/perception)

du'u vs jei: du'u is the claim; jei is the truth value (how true the claim is, including fuzzy “shades”). Curiosity or doubt often fits jei better than plain du'u:

mi kucli le du'u la .frank. cu bebna I'm curious whether Frank is a fool.

mi kucli le jei la .frank. cu bebna I'm curious how true it is that Frank is a fool.

Truth still lives in the outer predicate: mi djuno le du'u … only works for facts you actually know; the abstraction itself does not “contain” truth.

x₂ of du'u — linguistic form: du'u has a second place: a piece of language that expresses the bridi. le se du'u (or le se du'u … with the predication filled) is the usual sumti when someone said something equivalent to a claim without quoting exact words:

la .djan. cusku le se du'u la .frank. cu bebna John says something to the effect that Frank is a fool.

That differs from lu … li'u, which asserts he used those exact Lojban words.

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ni: Amounts#

ni abstracts a measurable quantity:

ni

x₁ is the amount/degree of [bridi]

le ni le pixra cu blanu the amount of the picture being blue → how blue the picture is

mi zmadu do le ni mi clani I exceed you in how tall I am. → I am taller than you. (comparing amounts)

ni only makes sense with measurable properties. "The amount of Jane being a mother" (le ni la .djein. mamta) is meaningless — motherhood isn't measurable on a scale.

ka vs ni:

le pixra cu cenba le ka ce'u blanu The picture varies in the property of being blue. (blueness comes and goes — yes/no)

le pixra cu cenba le ni ce'u blanu The picture varies in how blue it is. (the degree of blueness changes)

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jei: Truth Values#

jei abstracts the truth value of a proposition — is it true or false, and to what degree?

le jei li re su'i re du li vo the truth value of 2+2=4 → evaluates to "true"

jei is most useful in fuzzy contexts where truth admits degrees, or when you want to explicitly handle truth as a value:

le jei do klama the truth value of whether you are going

mi djuno le jei do klama I know whether you are going.

jei has an x₂ place (like ni) for the scale or standard of “how true” — important in fuzzy logic; everyday speech often leaves it implicit.

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si'o: Concepts / Ideas#

si'o abstracts a concept or idea as it exists in someone's mind:

le si'o lo prenu cu simxu prami the concept of people loving each other

mi nelci le si'o la lojban. I like the idea of Lojban.

si'o is used for mental representations, ideals, and the conceptual content of thoughts — more subjective than du'u.

x₂ place: x₁ is the concept [bridi]; x₂ is who holds it — a person, a community, or a “mind” in the broad sense. When you fill x₂, close the abstraction bridi with kei first, then be:

le si'o lo prenu cu simxu prami kei be la .teris. The concept of people loving each other, as Terry conceives it.

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Indirect Questions with kau#

Recall from Chapter 6 that kau marks the questioned element in an indirect question. The containing abstractor is usually du'u:

mi djuno le du'u ma kau klama I know who is going. (ma kau = the questioned element)

mi djuno le du'u xu kau do klama I know whether you are going.

mi na djuno le du'u do klama ma kau I don't know where you are going.

Without kau, the question word is direct. With kau, the whole thing becomes an embedded indirect question.

Why kau? Inside le du'u, a bare ma (or other question fragment) still parses as a direct question — Who is it that I know goes? — not as an indirect “I know who goes.” kau marks the questioned piece as the answer sought in the embedded reading.

Sometimes you can avoid kau: when the questioned part is a sumti, djuno’s fi place can carry “what is known about X”:

mi djuno fi le pu klama be le zarci I know something about the past goer to the store — often glossed as *I know who went._

That paraphrase is loose: the listener must infer that identity is what is known, not (say) the person’s shoe size. When the questioned bit is not a sumti — for example, a connection or operator — le du'u … kau is usually the only clean option.

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Sumti Raising: tu'a and jai#

Sometimes a gismu's place structure requires an event or property abstraction, but you want to use a plain sumti. tu'a and jai help bridge this gap.

tu'a — "some event or fact about [sumti]"

An informal sumti-raiser. Instead of constructing a full abstraction, wrap the relevant sumti in tu'a:

mi djica tu'a do I want something involving you. (≈ I want you to do something)

mi djica le nu do klama (full version) I want the event of you coming.

tu'a do ≈ le nu do co'e (some unspecified event about you). It's much shorter and is natural in speech.

mi troci tu'a le kabri I try something with the cup. (≈ I try to lift / fill / clean it — context decides)

jai + modal — the precise alternative

jai promotes the tag argument of a modal to x₁ of the selbri. This is the formal mechanism behind sumti-raising:

le nu mi djica cu jai mu'i klama fai mi My wanting is the motivation for the going, which I do.

Here the event "my wanting" is raised to x₁, and the original x₁ (mi) is displaced to fai (the special place created by jai). In practice, tu'a handles most casual sumti-raising; jai is for precise grammatical control.

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Lojban Sumti Raising with ni and li'i#

Two other abstractors interact with sumti-raising:

ni — "the amount/degree that"

Used with quantity-predicates like barda (big), melbi (beautiful), zmadu (exceeds):

le ni le zdani cu barda the amount of the house's bigness = the house's size

mi zmadu do le ni mi barda I exceed you in the amount that I am big. = I am bigger than you.

This is Lojban's way of making scalar comparisons exact.

li'i — "the experience of"

Abstracts a subjective experience:

le li'i mi cortu cu pluka nai The experience of my being in pain is not pleasant.

li'i is used when the experiential quality matters, not just the event.

x₂ place: x₁ is the experience of [bridi]; x₂ is the experiencer. Example with kei be:

mi morji le li'i mi verba kei be mi I remember my experience of being a child.

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su'u: The General Abstractor#

su'u is a "catch-all" abstractor — it abstracts without specifying what kind of abstraction applies. Its unique feature is an x₂ place that lets you specify the abstraction type explicitly:

x₁ is the [x₂-type] abstraction of [bridi]

Examples:

le su'u le ci smacu cu bajra The abstract nature of the three mice running. (type unspecified — "See how they run!")

le su'u mi klama kei be lo fasnu The event-abstraction of my going. (x₂ = lo fasnu specifies it's an event, same as le nu mi klama)

su'u can substitute for any other abstractor when you want to be vague or when no existing abstractor fits:

le su'u la .iecuas. cu jmive The abstract nature of Jesus's living. (neither event, property, nor amount — something more like "the mystery/fact of")

Important: when filling the x₂ place, use kei be to close the abstraction bridi first:

le su'u mi klama kei be lo fasnu ✓ le su'u mi klama be lo fasnu ✗ (the be attaches inside the bridi, modifying klama)

The same kei be pattern applies whenever you specify x₂ on su'u, si'o, or li'i (and similarly for other abstractors with an outer be): without kei, be is read as part of the inner bridi, not as tagging the abstractor’s second place.

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Event Abstractors and ZAhO Tenses#

The four NU event-type abstractors (nu, pu'u, za'i, zu'o, mu'e) have a systematic correspondence with the ZAhO event-contour tenses. The ZAhO cmavo describe which phase of an event the bridi refers to.

The ZAhO cmavo#

Which ZAhO apply to which event types#

Not all ZAhO make sense with all NU types:

Examples in use:

mi co'a citka le sanmi I start eating the meal. (co'a = beginning edge of the eating event)

mi ca'o citka le sanmi I am in the middle of eating the meal. (ca'o = ongoing process)

mi ba'o citka le sanmi I have finished eating the meal. (ba'o = after-the-event perspective)

mi za'o citka le sanmi I am still eating the meal past its natural end. (za'o = excessive continuation)

mi co'i citka le sanmi I eat the meal. (as a completed achievement; the whole event as a point)

The ZAhO tenses are placed in the normal tense slot before the selbri. They can be combined with PU tenses:

mi pu co'a citka I had just started eating. (in the past, at the starting edge)

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Abstractor Connection#

Abstractors themselves can be connected with logical connectives, just like selbri:

le nu joi ka la .alis. cu klama the event and/or property of Alice's going

Purely logical connection between abstractors of the same type is also possible — two events, two properties, etc.:

le nu mi cadzu .e le nu do bajra the event of my walking and the event of your running

joi (non-logical connective: "combined mass") combines two abstractions:

le nu .e ka do cadzu the event and property of your walking

This is advanced and rare, but useful when you need to speak about multiple aspects of the same bridi simultaneously.

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Comparative lujvo (-mau, -me'a)#

“More than” / “less than” often use lujvo ending in -mau (zmadu) and -me'a (mleca) instead of bare zmadu/mleca — the places are easier to fill.

mi citmau do lo nanca be li xa I am six years younger than you. (citno + zmadu)

do citme'a mi lo nanca be li xa You are six years less young than me. (parallel mleca form)

Packed comparatives like nelcymau (like-more) and klamau (go-more) follow regular place conventions: the two things compared usually line up with the first places of the embedded relation. The forms and their places:

For “more than before” without naming a rival, use increase/decrease (zenba, jdika) rather than an empty zmadu second place. Compare:

mi ca tsamau I'm stronger now — but tsamau is still a -mau comparative; z₂ is often read as “than someone,” not “than before.”

mi ca tsaze'a I increase in strength. → I'm stronger now (no unnamed rival).

traji superlatives (citrai, balrai, …) pick the extreme member of a set:

la djudis. cu citrai lo'i lobypli Judy is the most expert Lojbanist.

la .ainctain. cu balrai lo'i skegunka Einstein is the greatest scientist. Tanru-style comparatives in depth: Chapter 15.

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Summary of NU Abstractors#

Key rules:

• Abstractions are closed by kei (elidable at end or before cu)
• ce'u marks the open slot in ka (and sometimes ni) abstractions
• Use du'u for knowing/believing/saying; nu for events you perceive/cause
• kau in a du'u abstraction creates an indirect question
• tu'a = quick sumti-raiser (some event about [X]); jai = precise promotion via modal

su'u — the general/vague abstractor:

• x₁ is the [x₂-type] abstraction of [bridi] — type specified in x₂
• Use when no other NU fits, or to be deliberately vague about abstraction type
• kei be required to close the bridi before filling x₂: le su'u … kei be lo fasnu
• du'u also has an x₂ (linguistic expression); see le se du'u above

ZAhO event contours (tense aspect particles):

• pu'o = before event; ca'o = during; ba'o = after
• co'a = starting edge; co'u = ending edge; co'i = whole event as point
• de'a = temporary pause; di'a = resumption; mo'u = natural end; za'o = past natural end
• Combine with PU: pu co'a = had just started
• ZAhO applicability by event type: pu'u (process) takes all; za'i (state) no za'o/mo'u; zu'o (activity) no sharp start/end; mu'e (point) no ca'o

Chapter 13. Negation & Logic#

Two Kinds of Negation#

English "not" is slippery. Consider:

John didn't go to Paris from Rome.

Does this mean he went somewhere else instead of Paris? That he departed from somewhere other than Rome? That he didn't travel at all? English doesn't say.

Lojban separates these into two distinct systems:

1. Bridi negation (na) — contradictory negation, denies the whole claim
2. Scalar negation (na'e, no'e, to'e) — says the value is "other than" the stated one

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na: Bridi Negation#

na before the selbri negates the entire bridi — making a clean logical contradiction:

mi klama le zarci I go to the store. (true)

mi na klama le zarci It is not the case that I go to the store. (the whole claim is false)

na has exactly one meaning: the bridi is false. If the bridi was true, na-bridi is false; if the bridi was false, na-bridi is true. This is classical contradictory negation.

na goes right before the selbri (after cu if present):

mi cu na klama le zarci (legal) mi na cu klama le zarci (legal — na can precede cu)

na can appear inside abstraction bridi too:

mi na gleki le nu mi klama le zarci I am not happy about the event of going to the store.

mi nelci le na melbi I like the one who is not beautiful.

Double negation cancels out:

mi na na klama = mi klama I do go. (na na = positive)

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na vs. no#

Don't confuse na (bridi negation) with no (the number zero) or no'e (scalar mid-point). They are entirely different particles.

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na'e: Scalar Negation#

na'e before a selbri or brivla says "other than [X]" — some different value on the same scale applies:

mi na'e klama le zarci I do something other than go to the store. (maybe I stay near it, circle it, etc.)

This is not the same as na! na'e klama says a different relation holds, not that nothing holds. It's a positive assertion that some other going-related thing is true.

na'e inside tanru targets just the following word:

mi na'e cadzu klama le zarci I go to the store in a non-walking manner. (still going, just not walking)

mi cadzu na'e klama le zarci I walk (but don't go to) the market. (walking is involved, destination is different)

To negate a whole tanru, use na'e ke … ke'e:

mi na'e ke cadzu klama ke'e le zarci I do something other than (walk-go) to the market.

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The Scalar System: na'e, no'e, to'e#

Lojban provides three levels on a scale:

mi melbi — I am beautiful. mi na'e melbi — I am other-than-beautiful. (could be ugly, neutral, or something else) mi no'e melbi — I am medium-attractive. (neutral) mi to'e melbi — I am ugly. (explicit opposite)

le zarci cu barda — The store is big. le zarci cu no'e barda — The store is medium-sized. le zarci cu to'e barda — The store is small.

to'e asserts the polar opposite, so it's a strong positive claim. na'e is vaguer — it just says "not this point."

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nai: Attitudinal Negation#

In attitudinals (Chapter 7), -nai is a suffix that inverts the attitudinal:

.ui — happiness → .uinai — unhappiness .ai — intent → .ainai — lack of intent / indecision

This is a separate particle from na and na'e — it only applies inside attitudinals and logical connectives.

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Negation in Questions#

xu asks whether the bridi is true (Chapter 6). Answers reuse the same bridi with na or abbreviate with go'i.

Straight question, negative answer:

xu la .djan. pu klama Did John go?

na go'i No — expands to la .djan. na pu klama (John didn’t go).

You may shift tense in the answer; na and the tense can appear in either order, which can change scope (see below):

na ba go'i ≈ la .djan. na ba klama — No — he won’t go. ba na go'i ≈ la .djan. ba na klama — No — later [it is false that] he goes. (subtle ordering effects)

Scalar “no”: na'e go'i = “other than the previous” — e.g. John didn’t go, he called (equivalent to putting na'eke after the tense before klama).

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Negative questions: xu na … and ja'a go'i#

If the question itself contains na, a bare go'i repeats including the na — it does not mean “yes” in English sense:

xu la .djan. na pu klama Is it true that John didn’t go?

go'i [Repeats:] John didn’t go. — affirms the negative question (often what English calls “yes, he didn’t”).

To assert the positive bridi instead, replace na with ja'a (same place na would occupy):

ja'a go'i John did go. — ja'a is the affirmative counterpart of na (Pragmatic Negation: ja'a below).

So: xu na go'i ↔ “Is it false that …?”; answer with ja'a go'i when the underlying claim is true, not plain go'i.

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Scope of na#

na always negates the entire bridi in which it appears. It does not narrow to just one sumti or one piece of the selbri. When you need to negate just a slot's content, put the negation in an inner bridi:

mi na klama le zarci ki'u le nu le karce cu spofu This negates the whole sentence "I go to the store because the car is broken" — saying the whole thing is false.

But if you want to say "I don't go because the car is broken (though I don't go for other reasons)":

le nu mi na klama le zarci cu se krinu le nu le karce cu spofu The event of my not-going to the store is caused by the car being broken.

Here na is inside the event abstraction, not at the top level.

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Negation and Quantifiers#

Negation interacts with quantifiers in important ways. Full logical quantifier negation is covered in Chapter 16, but the basics:

lo gerku cu na blabi — Some dogs are not white. (true in general) na ku lo gerku cu blabi — It is not the case that [any] dog is white. (claims NO dogs are white)

The position of na relative to quantifiers changes the logical meaning drastically. This is the classic scope-of-negation problem that Lojban handles precisely.

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Pragmatic Negation: ja'a {#pragmatic-negation-jaa}#

ja'a is the explicit affirmative particle — "indeed, truly":

mi ja'a klama — I indeed go. (emphatic yes)

It's mostly used to explicitly undo a previous negation or to provide strong contrast:

do na klama .i mi ja'a klama You don't go. I do go.

ja'a belongs to the same selma'o NA as na, and serves as its explicit opposite.

With go'i, ja'a replaces a na in the repeated bridi — essential for answering xu na … with a positive fact (Truth questions above).

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Sumti Negation#

So far we've seen how to negate the bridi (the whole claim) and how to negate a selbri (scalar negation). Lojban can also negate a sumti — specifically, negate what fills a numbered place.

The main tool is naku (or na ku) before a sumti. It shifts the negation to bind the following quantified sumti:

mi klama naku le zarci I go to a non-store. (what I go to is not a store)

More precisely, quantifier negation with naku works like prenex logic. Pushing naku leftward past a quantifier reverses the quantifier:

mi viska no le prenu = mi na viska ro le prenu I see none of the people. = It's not the case that I see all of them.

Numbers as quantifiers can express sumti negation directly:

mi klama le no zarci — impossible (there are zero stores to go to) mi na klama le zarci — I don't go to the store (bridi negation)

The difference matters with existential claims:

lo no gerku cu blabi — no dog is white (zero dogs fit) — effectively "there are no white dogs" na ku lo gerku cu blabi — it's not the case that some dog is white (same, different logical form)

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na'i: Metalinguistic Negation#

na'i is the metalinguistic negation — it signals that something is wrong with what was just said, not that the bridi is false:

do'u na'i Something wrong just happened (the utterance had a false presupposition, grammatical error, or category mistake)

xu do klama le zarci .i na'i le zarci cu se klama Are you going to the store? — [False presupposition:] The store is somewhere one goes. (correcting the frame, not just answering no)

na'i contrasts with na:

• na = the bridi is false (contradictory negation)
• na'i = something about the utterance is wrong — a presupposition fails, a category is confused, or the question doesn't apply

mi bilma .i do pu'i jbena na'i I am sick. You were born, [metalinguistically negated — something is off with that claim].

na'i is used in discourse as a polite way to say "I'm not disagreeing with the facts, but the framing is wrong."

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naku: Negation Scope and Quantifier Interaction#

The full treatment of naku shows how it interacts with quantifiers in a prenex:

naku ro da poi prenu cu morsi = su'o da poi prenu zo'u da na morsi Not everyone dies. = Some person doesn't die.

The key rule: naku before a universal quantifier reverses it to existential (and vice versa):

This is De Morgan's law for quantifiers — covered more thoroughly in Chapter 21.

naku outside a prenex moves the scope of negation earlier in the sentence, letting it bind more:

mi na klama le zarci — bridi negation (I don't go to the store) naku mi klama le zarci — same semantics, but the na is fronted for emphasis or scope clarity

In complex nested bridi, the exact position of na vs. naku changes what is negated. When in doubt, use the prenex form with naku to make scope fully explicit.

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Sumti Negation: na'ebo#

Just as na'e applies scalar negation to a selbri, na'ebo applies it to a sumti — the argument, not the predicate.

na'ebo le gerku cu batci mi Something other than the dog bites me.

The na'ebo targets the sumti le gerku and asserts that something other than what that sumti describes is the correct x₁. It makes a positive assertion: something else does the biting, though we don't say what.

By contrast, to negate the sumti with a zero quantifier (contradictory negation):

no le gerku cu batci mi None of the dogs bite me.

This is contradictory: it simply says the count is zero. na'ebo is scalar: something other than a dog is involved.

You can also use no'ebo (neutral) and to'ebo (opposite) on sumti:

mi klama to'ebo la .bastn. I go to the opposite of Boston. (the antipodal city)

These are relatively rare but useful in precise discourse.

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Specifying the Scale in Scalar Negation#

When you use na'e, no'e, or to'e, the scale being used is usually implied by context. Sometimes you need to be explicit. The sumti tcita ci'u (on a scale of X) can be attached to the negated selbri with be:

le stizu cu na'e xunre be ci'u loka skari The chair is non-red on the scale of color-ness.

This explicitly identifies that xunre is being negated within the color scale, ruling out interpretations where "other than red" might mean "other than the chair being red in general."

For to'e (polar opposite), the scale is particularly important:

ta to'e melbi That is repulsive/very ugly. (the opposite end of the beauty scale)

ta no'e melbi That is plain/ordinary-looking. (the neutral midpoint)

The rafsi for these NAhE particles let them appear in lujvo:

• -nal- from na'e (non-)
• -nor- from no'e (neutral-)
• -tol- from to'e (opposite-of-)

Examples: nalmle (non-beautiful), tolmle (ugly/repulsive), normle (plain-looking).

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nai on Interval Modifiers: Scalar vs Contradictory#

The suffix -nai behaves differently depending on what it is attached to:

On tenses and modals (PU, BAI): nai is contradictory — it simply negates the tense:

mi punai klama le zarci I [not-past] go to the store. (= it is not the case that I went)

This is equivalent to mi na pu klama le zarci.

On TAhE, ROI, and ZAhO (interval and aspect particles): nai is scalar — it says the specified frequency/phase is not accurate, but does not say zero:

mi paroinai dansu le bisli I [once-not] dance on the ice. I dance on the ice either zero times or two-or-more times within this period.

This is very different from English "not once" (which means never). In Lojban, paroinai only rules out "exactly once."

mi ca'onai citka I am [not in-the-middle-of] eating. (= I'm not currently in the eating process)

On attitudinals (UI, CAI): nai is polar — it takes the attitudinal to the opposite end of its scale:

.uinai — unhappy (opposite of .ui happy) .ienai — disagree (opposite of .ie agree)

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naku and Tense: Scope Order Matters#

When naku appears in the same bridi as a tense marker, their order determines meaning. na (or naku) and tense are in the same structural position (before the selbri), and whichever comes first has wider scope:

Tense outside negation: naku inside pu

mi pu na klama le zarci I [in-the-past] [not-went] to the store. = Past is asserted; what is negated is the going. Meaning: There was a past moment at which I was not-going to the store.

Negation outside tense: naku wraps pu

mi na pu klama le zarci It is not the case that [I past-went] to the store. = The whole past-going claim is false. Meaning: I did not go to the store in the past. (No past-going event exists.)

These two can have different truth conditions in edge cases:

• pu na klama: there was a time when I was in a non-going state (compatible with "I went later")
• na pu klama: there is no past event of going at all (stronger)

The general rule: whichever scoping element (tense or negation) appears earlier in the spoken/written sentence takes wider scope over what follows it.

This matters most in:

• Quantified bridi with tense: ro le prenu pu na klama vs. na ro le prenu pu klama
• Modal + negation: mu'i le nu … na … (the modal is outside the negation) vs. na … mu'i le nu … (negation is outside the modal's scope)

When scope is ambiguous, use a prenex to make it explicit:

pu zo'u naku ro da broda In the past: not all things are broda (pu outside, naku inside the prenex)

naku zo'u pu ro da broda It is not the case that [in the past all things are broda] (naku outside, pu inside)

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nai on Abstractors#

The NU abstractors can also take -nai, forming negated abstractions that can be joined with logical connectives:

su'u jenai ni — the property, but not the measure

This construction parallels punai je ca = pu naje ca for tenses: compound abstractors can carry -nai on one arm the same way tenses do. Logically connected abstractors with negation are rare outside technical prose.

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Negation of other grammatical pieces (quick inventory)#

CLL groups every use of nai that is not ordinary na bridi negation. Most of these are already covered above or in Chapter 8; this is a roadmap:

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Affirmations#

Besides ja'a (NA — bridi affirmation), Lojban uses UI-family affirmations:

je'a — scalar affirmation (UI)

A discourse particle expressing that something is definitely the case, stronger than the default. Roughly "certainly" or "indeed so":

je'a go'i — Yes, indeed (stronger than just go'i)

jo'a — metalinguistic affirmation (UI)

Asserts that an expression is being used correctly or that a framing is appropriate, countering a na'i challenge:

na'i — Something is wrong with how this was said / the framing is off. jo'a — No, the framing is appropriate.

je'a and jo'a are used at the discourse/attitude level rather than as logical operators on truth values.

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Summary#

Key rules:

• na = whole bridi is false; na na = double negation = positive
• na'e = some different value holds (positive assertion of difference)
• to'e = specifically the opposite end of the scale
• Put na before the selbri; put na'e before the word it targets
• Scope of na is the entire bridi; use na'e ke…ke'e for tanru-scope scalar negation
• naku + universal quantifier = existential with na (De Morgan swap)
• na'i = metalinguistic, not logical — the framing itself is challenged
• Truth questions: na go'i = no; xu na … + go'i affirms the negative; use ja'a go'i to assert the positive bridi
• Minor nai: see quick inventory table — PU/BAI vs TAhE/ROI/ZAhO vs UI vs JOI/BIhI vs logical connectives

Sumti negation:

• no lo … = contradictory sumti negation (zero quantification)
• na'ebo = scalar sumti negation: "something other than [sumti]" (positive assertion)
• no'ebo = neutral sumti; to'ebo = opposite sumti

Scale specification:

• ci'u (on a scale of X) explicitly names the scale for na'e/no'e/to'e: na'e xunre be ci'u loka skari

nai suffix behavior:

• On PU/BAI tenses and modals → contradictory (simple negation)
• On TAhE/ROI/ZAhO interval/aspect particles → scalar (the specified frequency/phase doesn't hold, but not zero)
• On UI/CAI attitudinals → polar (opposite end of emotional scale)
• On NU abstractors → negated abstraction type; can be connected with logical connectives

Affirmations:

• ja'a = bridi affirmation (emphatic positive; counterpart of na)
• je'a = scalar affirmation (UI): "indeed/certainly so" — stronger than default
• jo'a = metalinguistic affirmation (UI): "the framing is correct" — counters na'i

Chapter 14. Morphology & lujvo#

Three Word Classes#

Every Lojban word belongs to exactly one of three classes, identifiable by its shape alone:

cmavo — structure words

Short particles with no consonant clusters: cu, le, mi, pu, je, lo, .i. They handle grammar — articles, conjunctions, tense markers, etc. Forms: V, CV, VV, CVV.

brivla — predicate words

Content words that end in a vowel and contain a consonant pair within the first five non-y letters. Three subtypes: gismu, lujvo, fu'ivla.

cmene — proper names

End in a consonant (hence always followed by a pause): la .teris., la .alis., la .lojban..

This three-way distinction is unambiguous: you can always tell which class a word belongs to by looking at (or hearing) its shape.

Recognizing words in a stream#

When splitting continuous Lojban text or speech into words, use morphology first (same tests as the parser):

1. Pauses and quotes — A . before a vowel-initial word is a real pause; la before a name requires pauses around cmene; ' between vowels is /h/. (See Chapter 19.)
2. cmene — Ends in a consonant; must be wrapped in pauses (and usually la).
3. cmavo — No consonant cluster; shapes V, CV, VV, CVV (and some longer compounds like cui, nai). If it could be cmavo or the start of brivla, the next letters decide.
4. brivla — Has a permissible consonant pair in the first five letters (counting only non-y letters) and ends in a vowel.

ZOI / lo'u quotations and other non-Lojban fragments follow their own rules — see Chapter 17. For the full decision procedure, see the Word Recognition section in this chapter below — it covers the boundary cases you will actually encounter when reading.

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gismu: Root Words#

The ~1350 gismu are Lojban's primitive vocabulary. They are always exactly five letters long, always start with a consonant, always end in a single vowel, and always stress the first (penultimate) syllable.

Two shapes:

• CVC/CV — e.g. klama, prenu, bridi
• CCVCV — e.g. blanu, tricu, mlatu

Each gismu comes from sounds in the six most-spoken natural languages (Mandarin, English, Hindi, Spanish, Russian, Arabic), blended to maximize recognizability across language backgrounds.

Examples:

No two gismu differ only in their final vowel (ensuring they can't be confused). Gismu are the building blocks for all compound words.

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rafsi: Word Pieces#

Each gismu has 2–5 rafsi (combining forms) used to build compound words. Rafsi are not standalone words — they only appear inside lujvo.

Complete rafsi shape typology:

Not every gismu has all six shapes — it depends on whether the gismu begins with CC, has a CV'V sequence, etc. Each gismu has at minimum a 4-letter and 5-letter long rafsi.

The tosmabru test:

When two CVC rafsi are joined, the result might accidentally look like a valid brivla starting at the wrong boundary. The test: if removing the final vowel of the whole lujvo and leaving the first five letters results in something that parses as a brivla, insert a y hyphen after the first CVC rafsi.

The test is named after the example: tosybau (one's-own-language — from tosto + bangu). Without y, tosbau is correct, but if the combination were tosmabru (animal species — tosto + mabru), the parser could split it as tos- + mabru (a gismu). The y prevents this: tosymabru.

In practice: whenever you join two CVC rafsi where the combined CC cluster at the join would be illegal or ambiguous, insert y. The lujvo-scoring algorithm tells you when this is needed.

Common rafsi for frequently used gismu:

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lujvo: Compound Words#

A lujvo is built by chaining rafsi together. It encodes a tanru (metaphorical combination) as a single unambiguous word with a fixed definition.

Process:

1. Identify the tanru: e.g. skami pilno (computer user)
2. Find rafsi: skami → sam-, pilno → pli or -pilno
3. Chain: sampli (computer-user)

More examples:

Unlike tanru (which are semantically vague), each lujvo has one specific fixed meaning. When you dictionary-define a lujvo, you lock in which interpretation of the underlying tanru it means.

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Hyphen Letters#

When chaining rafsi, consonant clusters must be maintained and the result must parse as a single word. Lojban uses letter hyphens to ensure this:

y-hyphen: inserted after a CVC rafsi when needed to prevent an illegal consonant cluster or word-boundary ambiguity:

pante tavla → patyta'a (not patta'a — tt is illegal)

mudri siclu → mudysiclu (not mudsiclu — would split)

r-hyphen / n-hyphen: inserted after CVV rafsi to create a needed consonant cluster:

soi + sai → soisai would be two cmavo → soisai needs r: sorsai (using r-hyphen)

When following rafsi starts with r, use n instead: ro'i + re'o → ro'inre'o

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zei: Ad-hoc lujvo#

When you need to form a lujvo-equivalent from words that have no rafsi (especially cmavo or fu'ivla), use zei as a joiner:

bridi zei valsi = brivla (exact equivalent)

by. zei livgyterbilma = B-disease (where by. is the letter B)

zei lets you create compound predicates from any words, including borrowed terms.

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fu'ivla: Borrowed Words#

fu'ivla (copy-words) are loanwords for concepts that don't fit neatly into Lojban's gismu system — biological species, foods, technical jargon, cultural terms.

The four formal stages:

Stage 3 structural requirements (the most important):

A stage 3 fu'ivla must:

1. Pass the brivla morphology test — it must look like a gismu or lujvo (not a cmavo or cmene).
2. Have a consonant cluster within the first five letters (to distinguish it from gismu length).
3. End in a vowel.
4. Not accidentally parse as an existing Lojban word.

Since many borrowed words don't naturally have a CC cluster early, a rafsi prefix is prepended to force the shape. The rafsi must end in a consonant, and the borrowed stem must begin with a consonant (so the join creates a CC cluster):

cac- (rafsi of cacra, hour) + tus → cactus is ambiguous; use kokso (coconut) built properly

tcati — tea (from Chinese chá; the initial tc cluster is native) ckafi — coffee (the ck cluster is provided by Lojbanization) blaci — glass (material)

If the foreign word doesn't naturally produce a CC cluster, prepend a meaningful rafsi as a classifier:

gri- (rafsi of grisi, grease) → grispolka = polka (dance related to jumping)

The choice of rafsi is semantic — it hints at the word's domain — but is otherwise flexible.

Examples of common fu'ivla:

• tcati — tea
• ckafi — coffee
• patxu — pot
• blaci — glass (material)
• mledi — mold/fungus
• xarju — pig

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Word Recognition Algorithm#

Because of these strict morphological rules, any string of Lojban sounds can be unambiguously segmented into words without spaces. The shapes uniquely identify word boundaries:

• cmavo: short, no consonant cluster
• gismu: exactly 5 letters, consonant cluster, ends in vowel
• lujvo: 6+ letters, consonant cluster in first 5, ends in vowel
• cmene: ends in consonant (pause follows)

This means Lojban speech is unambiguous at the word level before you even consider meaning.

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cmene: Lojbanization Rules in Detail#

Lojban names (cmene) must end in a consonant and be surrounded by pauses. Beyond those basics, the full rules are:

Consonant clusters inside cmene: Every consonant pair inside the name must be permissible by Lojban phonology rules (the same rules as gismu and lujvo). Impermissible clusters require a buffer vowel (usually y, i, or u) inserted between them.

Names ending in a vowel: Add a consonant, typically s or n:

• Mary → .meris. or .merin.
• Joe → .djos.
• Sue → .sus.

Stress: The default is penultimate stress, but non-standard stress can be marked by capitalizing the stressed vowel:

• Ivan (stress on first syllable) → .IVan. or .ivan. (lowercase assumes pen-ultimate)
• A name like .karlos. naturally stresses kar (penultimate of the two syllables)

Lojbanization strategy:

1. Identify the source pronunciation (not spelling).
2. Map each sound to the nearest Lojban phoneme.
3. Resolve impermissible clusters by inserting buffer vowels.
4. Ensure the result ends in a consonant.
5. Add a pause mark (period) before and after.

Examples:

When a name could parse as a brivla: If a name's shape matches brivla morphology (CC cluster, ends in vowel), add a final consonant to force cmene parsing. For example, a character named Prenu ("Person") would need to be .prenus. to avoid being parsed as the gismu prenu.

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Rules for Inserting Pauses#

Pauses are mandatory (not just recommended) in seven situations:

1. Before a cmene that begins with a vowel: The vowel would otherwise attach to the previous word. Write a period (.) before the name: .alis., .ivan..

2. After every cmene: The final consonant needs a clear pause boundary: la .djan. not la .djana.

3. Before and after SI/SA/SU (erasure words): These words erase what came before; they must be clearly bounded to avoid erasing the wrong thing.

4. After ZO (single-word quoter): zo quotes the immediately following word; a pause after the quoted word ends the quotation: zo .djan. cu cmene = the word "john" is a name.

5. Around ZOI and LA'O delimiters: The delimiter word before and after the foreign text must be surrounded by pauses so the parser knows it's a delimiter, not regular speech.

6. After text that ends in a consonant cluster (if the next word begins with a consonant): To prevent the cluster from appearing to bridge into the next word.

7. Around embedded non-Lojban text: Before and after any foreign-language passage embedded in Lojban speech.

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Lujvo Place Structures: Selecting What Matters#

A lujvo is built from a tanru, but its place structure needs to be determined — which places of the component gismu should survive in the final lujvo?

The standard method: take the place structure of the tertau (the main gismu, the last in the tanru), then add important places from the seltau where needed.

Example: mamta patfu (maternal grandfather)

• mamta (mother): x₁ is mother of x₂
• patfu (father): x₁ is father of x₂
• The lujvo mampa'u: x₁ is a maternal grandfather of x₂

The x₂ place of mamta (the child) and x₂ of patfu (the child) collapse — they're the same thing. The lujvo absorbs both into one x₂.

Dependent places are places of the seltau that are already determined by a place of the tertau. They don't appear in the lujvo's place structure because they're not independent:

balsoi (great soldier, from barda + sonci)

• sonci x₁ is a soldier of army x₂
• barda x₁ is big
• x₁ of barda is determined by x₁ of sonci (same entity)
• So: balsoi x₁ is a great soldier of army x₂ — barda's place collapses

Symmetrical vs. asymmetrical lujvo:

In a symmetrical lujvo, both components contribute equally and the relationship is reciprocal:

datpre (different person): x₁ is a person different from x₂ in x₃ (from drata + prenu — "other person" is symmetric: A differs from B ↔ B from A)

In an asymmetrical lujvo, one component modifies the other directionally:

balsoi = great soldier (the bigness modifies the soldier, not vice versa) zdamlatu = house cat (the house constrains the cat's type)

Most lujvo are asymmetrical — the seltau narrows the tertau's meaning.

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Comparatives and Superlatives#

Lojban expresses comparison through specific gismu and BAI particles, not through inflection:

zmadu — x₁ exceeds x₂ in property x₃ by amount x₄ mleca — x₁ is less than x₂ in property x₃ by amount x₄ dunli — x₁ equals x₂ in property x₃

mi zmadu do le ka barda I exceed you in the property of being big. = I am bigger than you.

le plise cu mleca le perli le ka titla The apple is less sweet than the pear.

The BAI shorthand (same meaning as zmadu / mleca, but attaching to another selbri; se conversion is often clearer than bare mau/me'a — see Chapter 10):

mi zmadu do le ka barda I am bigger than you.

mi mleca do le ka barda I am smaller than you.

Compact comparative lujvo (-mau, -me'a) — citmau, citme'a, nelcymau, klamau, and friends — plus zenba/jdika for “more than before” and traji-based extremes (citrai, balrai), are spelled out with CLL pointers in Chapter 12 (section Comparative lujvo). This section’s zmadu / mleca / traji material is the tanru-level companion.

Superlatives use traji. Places: x₁ = the extreme individual; x₂ = property (ka); x₃ = which extreme (defaults to “more”, i.e. ka zmadu); x₄ = the comparison set.

le traji be le ka barda bei zo'e bei le'i prenu The one who is most big among the set of people.

Relative clause (note ke'a for x₁ of traji, and zo'e for x₃ so x₄ can be the set):

le prenu poi ke'a traji le ka ce'u barda ku zo'e le'i prenu The person who is biggest among the people.

The compound verai (from ve + rai) tags traji’s fourth place — “superlative among …” — and is often the clearest shortcut:

le prenu cu barda verai le'i prenu The person is biggest among the people.

The bare rai cmavo tags traji’s first place (“with superlative …”); for “among a set”, prefer verai or an explicit traji sentence.

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Notes on gismu place structures#

Unlike lujvo guidelines, gismu places were fixed case by case (the list is now frozen). A few pressures shaped them — the same ones that also influence sensible lujvo design:

Worked examples (CLL-style):

• xekri — only “x₁ is black”: color is subjective; no “objective standard” place (ci'u or a lujvo can add one).
• jbena — time and location places exist so le te jbena / le ve jbena are simple terms (birthday, birthplace), even though tense tags usually carry time/place for other bridi.
• rinka — x₁ causes x₂; no agent place, because causes need not involve someone doing something (use gasnu / lujvo when you need an agent).
• cinfo — x₂ breed exists for regularity across animal/plant gismu, even when the species is not very diverse.

Ordering habits (not strict rules): places are often ordered by salience — e.g. klama puts the goer before the route. When both appear, destination tends to come before origin. “Under conditions” / “by standard” slots are often last.

ckaji (has / is characterized by) — important for property talk and adjacent to comparatives: x₁ is the entity, x₂ is the property (usually le ka …).

le gerku cu ckaji le ka xunre The dog has the property of being red.

For machine-checkable place types and glosses, see the project’s typed gismu reference (and the underlying formal-_gismu_.tsv in the source tree).

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Lujvo Place Structures#

When you form a lujvo, you do not simply inherit the place structure of the tanru it came from. A tanru always carries the place structure of its right-hand word (the tertau), but a lujvo needs to take all of its components into account. This section explains how to think about which places a lujvo should have and in what order.

The seltau and tertau#

In a two-part tanru — and therefore in a two-part lujvo — the left component is called the seltau (modifier) and the right component is called the tertau (head). The overall concept is a type of whatever the tertau describes, modified by the seltau.

For example, in gerku zdani (dog house), zdani is the tertau (it's a type of house) and gerku is the seltau (the dog part is the modifier). The resulting lujvo gerzda describes a kind of zdani, not a kind of gerku.

How a lujvo gets its meaning#

A tanru is deliberately vague: gerku zdani just means "some house that has something to do with some dog." The relationship between the seltau and tertau is left open. A lujvo, by contrast, locks in one specific interpretation. The lujvo-maker picks the most useful and most obvious relationship.

Almost always, the best relationship is found by noticing that one place of the seltau refers to the same thing as one place of the tertau. For gerzda:

• zdani: z1 is a house for inhabitant z2
• gerku: g1 is a dog of breed g2

A dog living in a house means z2 (the inhabitant) is the same as g1 (the dog). That overlap is the relationship. Since they refer to the same thing, that place only needs to appear once in the lujvo — it is merged.

So the tentative place structure of gerzda becomes:

z1 is a house for dog z2=g1 of breed g2

Dependent places#

A place is dependent on another if you can predict its value once the other is known. For gerku, g2 (the breed) is dependent on g1 (the dog): once you know which specific dog you're talking about, the breed is determined. Dependent places that come from the seltau can often be dropped from the lujvo's place structure.

So in gerzda, the breed place g2 gets dropped — you're describing a doghouse, not a dog, so the breed is incidental. The final place structure is simply:

z1 is a house for dog z2

However, there's an important exception: dependent places that come from the tertau are kept. The tertau defines what kind of thing the lujvo is, and dropping its places would make the lujvo too different from the base word. If dropping a tertau place seems necessary, it's usually a sign that you've chosen the wrong tertau.

Sometimes a dependent place from the seltau is still important to keep. If you were making a lujvo for school building (kuldi'u, from ckule dinju), you'd want to keep the subject of the school even though it's technically dependent on the school identity, because music school building and elementary school building are very different.

Symmetrical and asymmetrical lujvo#

When the overlap is between the first place of the seltau and the first place of the tertau — both components describing the same individual — the lujvo is called symmetrical.

Example: balsoi (great soldier), from banli sonci:

• banli: b1 is great in property b2 by standard b3
• sonci: s1 is a soldier of army s2

Here b1 = s1 (the same person is both great and a soldier). That's the symmetrical pattern.

When the first place of the seltau matches some other place of the tertau, the lujvo is asymmetrical.

Example: gerzda above — g1 (first place of gerku) matches z2 (second place of zdani), not z1. The lujvo is about the house, not the dog.

In principle, any asymmetrical lujvo could be made symmetrical by applying a SE conversion to one component. gerzda (asymmetrical) could be replaced by gerselzda (symmetrical: dog-housed-in), but that would make the first place the dog rather than the house, which is backwards for the meaning doghouse. Shorter and more direct is usually better.

Ordering the places#

Once you've selected which places survive, you need to arrange them in a sensible order. The rules are:

For symmetrical lujvo: tertau places come first, then any surviving seltau places.

Example: balsoi place structure:

b1=s1 is a great soldier of army s2 in property b2 by standard b3

The tertau (sonci) places come first: s2 (army). Then the surviving seltau (banli) places: b2 (property), b3 (standard).

For asymmetrical lujvo: the seltau places are inserted immediately after the tertau place they share. Remaining tertau places follow after.

Example: dalmikce (veterinarian, from danlu mikce — animal doctor):

• danlu: d1 is an animal of species d2
• mikce: m1 is a doctor to patient m2 for ailment m3 using treatment m4

Here d1 = m2 (the animal is the patient). Place structure:

m1 is a doctor for animal m2=d1 of species d2 for ailment m3 using treatment m4

After the shared place m2=d1, the remaining seltau place d2 (species) is inserted, then the remaining tertau places m3 and m4.

Lujvo with more than two parts#

Multi-part lujvo are easiest to understand as nested binary tanru. Treat the whole lujvo as having two components, where one or both of those components may themselves be lujvo.

Example: bavlamdei (tomorrow), from ba (future) + lamji (adjacent) + djedi (day). Think of it as bavla'i (next-after) + djedi (day), where bavla'i is itself an intermediate lujvo.

Build the place structure by composing the component place structures in the same way as for two-part lujvo, working from the inside out.

Eliding SE rafsi from the seltau#

It is very common to drop the rafsi for SE conversion words (se, te, ve, xe) from the seltau of a lujvo, producing a shorter word. This is generally safe when the intended interpretation is clear and the alternative (without SE) would be implausible.

Example: ti'ifla (bill, proposed law), from stidi flalu (suggest + law). The second place of stidi (what is suggested) lines up with the first place of flalu (the law), but that means we'd normally need selti'i (suggested-thing) as the seltau. ti'ifla drops the sel- but still carries the same place structure as selti'ifla would have.

The convention is: give such lujvo the place structure they would have with the appropriate SE inserted. Just be aware that ambiguity is possible if another interpretation is equally plausible.

Eliding SE rafsi from the tertau — don't!#

Dropping SE from the tertau is much more dangerous and should generally be avoided.

Consider translating blue-eyed. You might be tempted to use blakanla (from blanu kanla, blue + eye). But Jack is not an eye — he has eyes. The correct tertau is selkanla (bearer-of-eyes). Using the wrong tertau produces a lujvo whose first place is the eye, not the person with the eye, which means you'd always need se blakanla to get to the right referent. Instead, use blaselkanla with the SE made explicit.

Eliding KE and KEhE rafsi#

Grouping cmavo ke and ke'e are often dropped from lujvo for brevity. This is usually fine when the correct grouping is obvious from context or plausibility.

Example: zernerkla (to sneak in) almost certainly comes from zekri ke nenri klama (crime-(inside-go)), since zekri nenri (crime-inside) makes little sense as a unit. The dropped ke doesn't cause confusion here.

However, be careful when the alternative grouping is also plausible — two different lujvo with different meanings can result from the same rafsi sequence depending on how the implicit grouping is read.

Note: if you want to apply a scalar negation (na'e, to'e) or SE conversion to an entire lujvo, it is safer to keep them as two words or use an explicit ke rafsi rather than just prepending the conversion rafsi.

Abstract lujvo#

NU abstractors (nu, ka, ni, du'u, etc.) can participate in lujvo construction. When they do, all the places of the abstracted predicate become extra places of the lujvo, shifted down by one to leave room for the abstraction event place at position x₁.

Example: nunkla (from nu klama, event-of-going):

nu1 is the event of k1's going to k2 from k3 via k4 by means k5

The nu place comes first (x₁ = the event), then all five places of klama follow as x₂–x₆.

For abstractors that have a second place (like ni, where x₂ is the measurement scale), that second place is placed after all the predicate places rather than before them.

The rafsi jax- corresponds to jai. When used in a lujvo, any fai place remains a fai place of the lujvo and does not participate in the numbered place structure.

Abstract lujvo are a common and productive pattern. English words ending in -hood, -ness, or -dom often map to nun- lujvo (from nu) or kam- lujvo (from ka): kambla = blueness.

Implicit-abstraction lujvo#

A particularly important pattern arises when the seltau effectively serves as the selbri of an event abstraction that fills a place of the tertau — and that abstraction relationship is not spelled out, but is instead deducible from the semantics.

Example: ctigau (to feed), from citka gasnu (eat + agent-of). The place structure of gasnu requires its g2 place to be an event. If the seltau is citka (to eat), the listener can deduce that an event of eating is involved, even though the nu abstractor rafsi is absent. The final place structure is:

g1 (agent) causes c1 to eat c2

This is equivalent to the more explicit but wordier nunctikezgau, but shorter and equally clear in context.

Other gismu with event places (rinka, basti, galfi, jgina, etc.) can form implicit-abstraction lujvo the same way. For example, likygau (to liquefy):

g1 causes l1 to be liquid of composition l2 under conditions l3

Use implicit-abstraction lujvo when the implicit event is unambiguously recoverable. If the symmetrical interpretation (both an agent and the thing being described) is equally plausible, the implicit-abstraction reading can be confusing.

Anomalous lujvo#

Some lujvo in common use don't perfectly follow the guidelines above — either because the seltau-tertau overlap is indirect, or because the veljvo doesn't fully capture the relationship. lange'u (sheepdog) is a classic example: a sheepdog is neither a sheep-breed dog nor a sheep that is a dog. Its real meaning is dog that controls a sheep flock, which requires a third component (jitro, to control) not present in the rafsi sequence. The shorter form lange'u is used as an abbreviation for the fuller but unwieldy terlantroge'u, and it inherits that longer lujvo's place structure.

Anomalous lujvo are acceptable and common — just be aware that they require more interpretive effort from the listener and should ideally have their place structure clearly documented.

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The Lujvo-Making Algorithm#

Given a tanru to turn into a lujvo, the formal process is:

1. For every component except the last, choose a 3-letter or 4-letter rafsi.
2. For the last component, choose a 3-letter (CVV or CCV) or 5-letter (long) rafsi.
3. Join the rafsi into a single string.
4. Insert hyphen letters where required (see the rules in the previous section on rafsi). Work right to left when checking, since the tosmabru test (step 5) depends on what comes after.
5. The tosmabru test: if the lujvo begins with one or more CVC-form rafsi followed by another CVC-form rafsi, check that the sequence cannot be misread as a cmavo followed by a shorter lujvo. If it can, insert a y-hyphen or choose a different rafsi.

The algorithm was designed to be implementable by computer, and lujvo-making software can generate all valid forms automatically.

Choosing the best form: the scoring algorithm#

When multiple valid rafsi combinations exist for the same tanru, the lujvo scoring algorithm selects the preferred dictionary form. The lowest-scoring form wins. Here's how the score is calculated:

Let L = total letter count (including hyphens and apostrophes), A = number of apostrophes, H = number of hyphen letters (y, r, n), and R = sum of rafsi type values (CVC/C rafsi score 2; CVC rafsi score 5; CVV-with-apostrophe score 6; CCV score 7; CVV-without-apostrophe score 8; long rafsi score lower). Let V = vowel count (excluding y).

Score = (1000 × L) − (500 × A) + (100 × H) − (10 × R) − V

In plain English, the algorithm strongly prefers shorter words, then penalizes apostrophes slightly less than full letters, then prefers fewer hyphens, then prefers "nicer" rafsi forms, and finally prefers more vowels as a tiebreaker.

Worked example (tanru gerku zdani, doghouse): using the rafsi choices for gerku and zdani, the scoring algorithm (described in the previous section) builds six hyphenated candidates. Their scores (lower = better dictionary form):

gerzda wins — fewest letters, no hyphens. The formula is the same as in the previous paragraph; computers (and the Scoring formula section above) list every tie-break. You do not need to score by hand unless you are coining a new lujvo for a dictionary.

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The Gismu Creation Algorithm#

If you've ever wondered why Lojban's root words sound vaguely familiar in multiple languages, here's why. Each gismu was created by a systematic algorithm designed to maximize recognizability across the six most widely spoken languages at the time: Chinese, English, Hindi, Spanish, Russian, and Arabic.

The process:

1. Find a word in each of the six source languages for the concept. Render it into Lojban phonetics (simplify consonant clusters, drop endings, map vowels).
2. Try every possible 5-letter gismu shape (CVCCV or CCVCV). For each candidate, score how closely it matches the six source-language forms: 3+ matching letters in order = their count; exactly 2 matching consecutive letters = 2; otherwise 0.
3. Divide each match score by the length of the source word and multiply by a language weight (proportional to speaker population, with second-language speakers counted at half). Sum the weighted scores.
4. Eliminate any candidate that conflicts with an existing gismu (identical, or identical except for the final vowel — since those would share a 4-letter rafsi).
5. The highest-scoring remaining form becomes the gismu. Occasionally a slightly lower-scoring form is used to provide a more useful rafsi.

This is why patfu (father) sounds like padre/paternal to Romance language speakers, nanmu (man) echoes nán (Chinese) and nam (Hindi), and so on.

Cultural and non-algorithmic gismu#

A small number of gismu were not created by the algorithm. They fall into a few groups:

• Lojban-specific concepts: words like cmavo, lujvo, lojbo, mekso, gismu itself — coined by combining or shortening other Lojban words. These are conceptually lujvo-like but are given gismu status (and rafsi) to keep lujvo built from them reasonably short.
• Assignable predicates: broda, brode, brodi, brodo, brodu — the five "pro-brivla" variables used for temporary selbri assignments (see Chapter 5).
• International scientific vocabulary: roots for chemical elements, SI units, and mathematical constants drawn from the international language of science.
• Cultural gismu: names for specific cultures, nations, or religions where the algorithm was inapplicable.

All non-algorithmic gismu end in -o, making them easy to recognize as exceptions.

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Also in this chapter: Recognizing words in a stream (boundary algorithm); gerku zdani scoring table (under Choosing the best form: the scoring algorithm).

Lujvo building steps:

1. Form a tanru expressing the concept
2. Find rafsi for each component
3. Chain rafsi left-to-right, inserting hyphen letters as needed
4. Verify: consonant cluster in first 5 non-y letters, ends in vowel
5. Optionally use zei for words without rafsi

Lujvo place structure:

• Default: start with tertau's places, add non-dependent seltau places
• Dependent places collapse (same entity as a tertau place)
• Symmetrical lujvo: both components equally present; asymmetrical: seltau narrows tertau

Comparatives:

• zmadu (exceeds) / mleca (less than) / dunli (equals) with le ka property
• BAI shortcuts: mau / se mau (from zmadu), me'a / se me'a (from mleca); verai (superlative among a set, from traji x₄); bare rai tags traji x₁ (“with superlative …”)

Chapter 15. Complex Selbri & Tanru#

Tanru: Metaphorical Combination#

A tanru is formed by placing two or more brivla together as the selbri. The first word (the seltau) modifies the second (the tertau), which carries the primary meaning.

mi sutra bajra I quick-type run → I run quickly / I am a quick runner.

la .djan. barda nanla John big boy → John is a big boy.

le zarci cu melbi zdani The store is a beautiful home-type. → The store is like a beautiful home (in some way).

The relationship between seltau and tertau is always vague — "X-type-of Y" — and the exact meaning depends on context. This is intentional: tanru are a productive, poetic tool, like English compound nouns.

Possible readings of klama jubme (goer table):

• a table that goes (wheeled)
• a table owned by a traveler
• a table for people who travel
• a table associated with going in some way

Lojban does not force a single reading. The speaker chooses a tanru for its evocativeness; the listener infers from context.

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Left-Grouping: The Default Rule#

When three or more brivla appear in a tanru without explicit grouping, left-grouping applies: the leftmost two bind first.

ta cmalu nixli ckule = ta (cmalu nixli) ckule That is a (small-girl)-type school.

The innermost tanru is cmalu nixli (small-girl), which then modifies ckule (school). So this is a school for small girls.

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bo: Right-Grouping#

bo causes the two brivla immediately surrounding it to bind more tightly than their neighbors. This creates right-grouping for those two words:

ta cmalu nixli bo ckule = ta cmalu (nixli ckule) That is a small (girls'-school). → a small school for girls

vs.

ta cmalu bo nixli ckule = ta (cmalu nixli) ckule = left-grouping (same as default here) That is a (small-girl)-type school.

Multiple bo also groups right-to-left:

ta cmalu bo nixli bo ckule = ta cmalu (nixli (... ckule))

The bo binds the last two it appears adjacent to. So A bo B bo C = A (B-bo-C), not (A-bo-B) C.

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ke … ke'e: Explicit Parentheses#

ke opens a grouping bracket and ke'e closes it (elidable at the end of a selbri). Everything inside is treated as a single tanru component:

ta ke melbi cmalu ke'e nixli ckule = ta (melbi cmalu) nixli ckule That is a ((beautiful small) girl)-type school.

ta melbi ke cmalu nixli ke'e ckule = ta melbi (cmalu nixli) ckule That is a beautiful (small-girl)-type school.

ke…ke'e is more readable than bo for complex groupings. It's like mathematical parentheses.

The five distinct groupings of melbi cmalu nixli ckule (beautiful / small / girl / school):

Notes:

• melbi cmalu = "beautifully small" — the first combines with the second
• The bo rule is right-grouping: the rightmost pair groups first
• The final ke'e in the last form is elidable at end of selbri
• English "pretty little girls' school" has only 2 parseable groupings in speech (stress/tone); Lojban has 5 and can distinguish all of them in writing

For comparison, the three-word cmalu nixli ckule already has the CLL "little girls' school" ambiguity:

Adding melbi at the front multiplies the possibilities because melbi can bind with (cmalu), with (cmalu nixli), or can stand alone before the whole rest.

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je: Logical Connection Within Tanru#

When you want a thing to be both X and Y (not "X-type of Y"), use je between the two brivla in the seltau position:

barda je xunre gerku (big and red) type-of dog → a dog that is both big and red

Without je:

barda xunre gerku = (big-type-of-red) dog → a dog whose redness is big (weird!)

The je resolves the independence of two properties:

ta blanu je zdani That is blue and is a house. (separately both, not "a blue-type house")

Other jeks work the same way inside tanru:

le bajra cu jinga ja te jinga The runner is a winner or a loser.

xamgu jo tordu nuntavla (good iff short) speech → speech that is good if and only if it is short

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co: Tanru Inversion#

Normally in a tanru, the last brivla is the head (the tertau). co inverts this: the word after co becomes the modifier, and the word before co becomes the head.

le gerku cu melbi = The dog is beautiful. le gerku cu melbi zdani = The dog is a beautiful-type home. le gerku cu zdani co melbi = The dog is a beautiful-type home. (same meaning, inverted)

More practically, co lets the main predicate come first, with the modifier following:

mi tavla co lojbo I speak in a Lojban-type manner. → I speak Lojbanically.

co has the widest scope of any tanru operator — it spans the whole selbri. Only one co can appear in a selbri at a time.

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je'i, joi and Other Connectives in Selbri#

joi in the seltau position creates a mixed mass tanru — the subject is "an inseparable mix" of two properties:

mi sofybakni joi xirma I am an inseparable-mix of (sofa-cow) and horse. (exotic example)

In practice joi is more commonly used between sumti (see Chapter 8), but it's grammatically valid inside selbri too.

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na'e and to'e in Tanru#

The scalar negation particles na'e and to'e (from Chapter 13) bind directly to a single brivla within a tanru:

mi na'e sutra bajra I (non-fast) run. → I run at a non-normal speed.

mi to'e sutra bajra I slowly run.

le to'e melbi prenu The ugly person.

They do not negate the whole tanru — just the brivla they precede.

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Tense, NA, and negation: where to look#

CLL threads tense, bridi negation, and scalar negation through the selbri in one long narrative. Friendly material splits by topic — use this map when you want “everything that can attach to a selbri”:

na (false) and na'e (non-) are different devices; tenses attach to selbri or bridi in stacks — order can matter. See Chapter 13 for na vs nai vs jo'ai, and Chapter 9 for tense–modal ordering.

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Place Structures of Tanru#

A tanru's place structure is always that of its tertau (the final/main brivla). The seltau's places are irrelevant to the bridi:

mi sutra klama le zarci I quickly go to the store.

Here sutra modifies klama, but the sumti slots are those of klama (x₁=goer, x₂=destination, etc.). The "speed" implied by sutra is inferred, not a numbered slot.

This is why tanru are semantically vague but grammatically clean: only the tertau's place structure is imposed.

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JAI: Converting Tags into Selbri#

jai is a special operator that converts a tense or modal tag into a selbri component, and simultaneously shifts the x₁ place.

Without jai, a modal tag like mu'i (because of / with motive) can only appear as a free prefix before the selbri:

mu'i le nu mi djica cu klama [With motive: my wanting] I go. (mu'i = motivated-by tag)

With jai, the tag becomes part of the selbri, and x₁ of the new selbri is the referent of the tag's value:

le nu mi djica cu jai mu'i klama My wanting is the motive for the going. (x₁ = le nu mi djica, filling the mu'i slot)

The most common use is with fai — the special place created by jai for the original x₁:

le nu mi djica cu jai mu'i klama fai mi My wanting is what motivates the going, which is done by me. (fai mi = the original x₁ "I" is pushed to fai)

jai with FA tags: when combined with a plain FA tag (like tu'a), jai converts the sumti into an appropriate selbri:

le gerku cu jai gau klama = The dog is the agent of going. (jai gau = agentive)

Practical common use — jai gau:

gau (the agent-of BAI cmavo) combined with jai is a clean way to express "causes X to happen":

mi jai gau cadzu le nanmu I cause the man to walk. (literally: I am the gau-agent of the man's walking)

This is more precise than using a causative tanru, because jai gau explicitly invokes the BAI causal role.

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Why ke/ke'e Exists: The Grammar Perspective#

You already know that ke…ke'e creates parenthetical grouping in tanru. But why is this a dedicated cmavo pair, rather than just how juxtaposition works?

The formal grammar defines tanru as a sequence of selbri components with left-grouping as the default. This means the grammar can't interpret "extra" juxtaposition as "tighter binding" without ambiguity. There is no way for the parser to know, from word order alone, that three brivla A B C should group as A (B C) rather than (A B) C.

bo resolves this for a pair — it marks the two words around it as a tightly-bound unit. But bo can only group two things at a time, and nesting bo bo bo… quickly becomes unreadable.

ke solves the general case: it acts as an opening parenthesis in the grammar, and ke'e is the explicit closing parenthesis. This gives the parser a clear left-bracket at an arbitrary point in the tanru sequence:

le melbi ke cmalu nixli ke'e ckule
       [        opens here        ]
= melbi [(cmalu nixli)] ckule

The grammar rule is: after seeing ke, the parser begins collecting a sub-selbri until it sees ke'e (or until the selbri ends, at which point an elided ke'e is assumed).

ke'e is almost always elidable at the end of the tanru, because the end of the selbri naturally closes it — but it is required when the grouping ends mid-tanru and another component follows. Compare:

le melbi ke cmalu nixli ke'e ckule — ke'e required (more components follow) le ckule ke cmalu nixli — ke'e elidable (tanru ends here)

The same ke/ke'e pair also works with connectives — connecting whole phrases inside a tanru bracket:

le ke cmalu ja barda ke'e nixli The (small or large) girl (ja = or, connecting the two modifiers as a unit)

Without ke, the ja would only connect the two words on either side of it. With ke, it spans the whole grouped phrase.

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me: Turning Sumti into Selbri#

Any sumti can be converted into a selbri using me:

le gerku cu me la fido. The dog is Fido-type. = The dog is like Fido / is Fido.

me creates a selbri meaning "is [the thing described by sumti]". It's used to:

• Make a sumti into a type: mi me la .lojban. = I am a Lojban-type person
• Borrowed or long names: le zgike cu me la'o gy. Beethoven gy. = the music is Beethoven-type (style associated with that name)

Close the me phrase with me'u (elidable at end of selbri):

le me la .alis. me'u cu melbi The Alice-type thing is beautiful.

me is particularly useful with cmavo that normally aren't selbri:

le se cusku be mi cu me zo blanu What I said was the-word-"blanu"-type. = I said the word "blanu".

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Other Kinds of Simple Selbri#

Besides brivla and tanru, several constructions yield a selbri:

Number words as selbri:

mi ci — I am three / I am the third le ci prenu — the three people (ci quantifies prenu)

Numbers and other PA cmavo can serve as predicates of quantity or ordinal:

le vo prenu cu xabju ti — The four people live here.

moi (ordinal) and other MOI cmavo:

mi pamoi — I am first. do remoi — You are second.

le nanmu pu klama le cimoi dinju The man went to the third building. (cimoi = ci + moi, third; not romoi, which would be ro + moi)

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Tanru Taxonomy: Patterns of Meaning#

Tanru meaning is deliberately vague — the exact relationship between seltau and tertau is left for context to determine. But in practice, tanru tend to fall into recognizable patterns. Knowing these patterns helps you both interpret and construct tanru naturally.

Asymmetrical Tanru#

In asymmetrical tanru, word order matters: clock pendulum is the type of pendulum used in clocks, while pendulum clock is the type of clock that uses a pendulum. Most tanru are asymmetrical.

Seltau = object of the tertau's action

The seltau names what the tertau-action is applied to or directed at:

Seltau = element type, tertau = the set

The seltau describes what the members of the tertau group are:

Seltau = whole object, tertau = a part of it

The seltau names the whole; the tertau is a component or detail of that whole:

Seltau = purpose or goal

The seltau describes what the tertau is for or aimed at:

Seltau = material

The seltau names the substance the tertau is made of:

Seltau = resemblance

The tertau resembles the seltau in some relevant way:

Seltau = location or time context

The seltau specifies where or when the tertau's referent belongs:

Symmetrical Tanru#

In symmetrical tanru, order does not significantly affect meaning — either word could come first. These often correspond to logical conjunction with je.

Things that are correctly described by both components

These are tanru where the referent genuinely fits both the seltau and the tertau. They could be rephrased with je (and):

Note that remna nakni means essentially the same as nakni remna — both describe something that is both human and male. This symmetry distinguishes these from cases where order matters.

Using These Patterns#

When you form a tanru, you are picking the pattern implicitly. When someone hears your tanru, they use pragmatics — the surrounding context — to decide which pattern fits best. This is by design: Lojban tanru are deliberately ambiguous. If you need precision, either:

1. Explain in context — let the surrounding bridi make the meaning clear
2. Convert to lujvo — a compound word with a fixed, agreed meaning
3. Use explicit connectives — je for "both", non-logical connectives for mixtures, etc.

The tanru system lets you coin new combinations freely. The cost is vagueness; the benefit is expressiveness and flexibility.

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Summary#

Tense / negation map: na vs na'e/to'e vs tense cmavo — see Tense, NA, and negation: where to look above.

Rules:

• Default tanru is left-grouping: A B C = (A B) C
• bo = right-group its two neighbors: A B bo C = A (B C)
• ke…ke'e = explicit grammar brackets; ke'e required when grouping ends mid-tanru
• je = both properties hold independently (not "A-type-of B")
• co = wide-scope inversion, one per selbri
• jai = tag-to-selbri conversion; the tag's value becomes x₁
• Tanru inherits tertau's place structure
• me = sumti → selbri (the sumti becomes a type)

Tanru taxonomy (patterns of meaning):

• Tanru meaning is deliberately vague; context determines the relationship
• Asymmetrical tanru: order matters; common patterns include seltau as object of action, material, location, purpose, resemblance, etc.
• Symmetrical tanru: order doesn’t affect core meaning; often equivalent to je (logical AND): remna nakni = human male = remna je nakni
• If precision is needed: explain in context, convert to lujvo, or use explicit connectives

Chapter 16. Advanced Connectives & Tenses#

Forethought Connectives: geks and guheks#

Chapter 8 introduced the basic connective forms. This chapter covers the complete system and edge cases.

Forethought bridi connectives (geks) signal the connection before either bridi. The separator gi appears between them:

ge la .alis. cu klama gi la .djan. cu cadzu Both Alice comes and John walks.

ganai mi klama gi do klama If I go, then you go.

Note the order: with ganai…gi, the first bridi is the antecedent (the "if" part).

Forethought selbri connectives (guheks) work inside selbri:

gu'e blanu gi xunre gerku a both-blue-and-red dog

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Termsets: Connecting Parallel Sumti#

When two bridi differ in multiple sumti simultaneously, you can use a termset to connect them all in parallel. The termset brackets are nu'i … nu'u (start/end):

nu'i ge mi gi do nu'u klama Both I and you go. (simplified: mi .e do cu klama)

More complex termsets arise when multiple slots change together:

nu'i mu'igi la .djan. lei jdini mi gi la .alis. le cukta do nu'u Connecting: John gave me money ←→ Alice gave you the book (by motivation)

Termsets ensure the logical connection applies to all the listed sumti simultaneously rather than distributing one sumti at a time. This is discussed in detail when dealing with modal connections (Chapter 10).

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giheks: Bridi-Tail Connectives#

A gihek connects two bridi-tails — the selbri plus following sumti, sharing the same x₁:

mi citka gi'e pinxe I eat and drink. (mi = shared x₁)

mi citka gi'a pinxe I eat or drink.

mi klama le zarci gi'enai cadzu I go to the store, but not walking. (I go but don't walk there)

Giheks are the most natural connective form when the subject is shared — they're much more concise than full .ije connectives.

Gihek forms:

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Tense and Aspect: The Full ZAhO System#

Chapter 9 covered the basic ZAhO aspect particles. Here's the complete system with their precise meanings:

An event has an internal structure: pre-start phase → start → middle → end → post-end phase.

mi pu'o klama — I am about to go. mi co'a klama — I start going. mi ca'o klama — I am in the process of going. mi co'u klama — I stop going. mi mo'u klama — I finish going (reached the destination). mi za'o klama — I keep going (past when I should have stopped). mi ba'o klama — I have gone (am in the resultant state). mi co'i klama — I went (the event of going, viewed as a whole point).

Combining tense and aspect:

Tense (pu/ca/ba) comes before aspect:

mi pu co'a klama — I started going [in the past]. mi ba mo'u citka — I will finish eating [in the future]. mi ca za'o tavla — I am still talking [now]. (past the appropriate time)

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Tense Intervals: Anchoring#

The interval particle (ze'i/ze'a/ze'u) can be further anchored with a following direction:

mi ca ze'ica cusku dei I [now] [short-interval-centered-on-now] say this. → I am now saying this sentence.

mi pu ze'iba klama A short time ago, I went [and the going extended forward toward now].

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When Tenses Stack#

Multiple tense elements in sequence describe a compound imaginary journey:

mi pu ba klama I [past-then-future] go → At some past moment, I was going to go.

le nanmu puzu vu batci le gerku Long ago and far away, the man bit the dog.

Each tense element adds a leg of the journey: pu (go back in time), zu (long distance in that direction), vu (long distance in space).

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Connected Tenses in Discourse#

Tense can be set for a whole passage using ki, the tense bookmark:

puki mi klama le zarci .i le zarci cu barda [Setting: past.] I go to the store. The store is big. (both sentences understood as past)

ki attaches to a tense, making it a reference point that persists:

puki — set "past" as current reference caki — set "present" as current reference baki — set "future" as current reference

Any subsequent bridi without an explicit tense is interpreted relative to the ki-set reference. Reset with caki to return to speaker-now.

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na'o and ta'e: Habitual and Iterative#

Two special tense-like particles express habituality and custom:

na'o — typically/usually (in the relevant context, events of this type usually occur)

mi na'o citka lo plise I typically eat apples. (not every time, but usually)

ta'e — habitually (as a regular habit of the x₁)

mi ta'e klama le zarci I habitually go to the store. (it's what I do)

ru'i — continuously (without break)

mi ru'i cadzu I walk continuously (without stopping).

These combine with the ordinary PU tenses:

mi pu ta'e klama le zarci I used to habitually go to the store.

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All 16 Truth Functions#

A logical connective is fully described by its truth table — what happens in each of the four cases (T+T, T+F, F+T, F+F). With four slots, each can be true or false independently, giving 16 possible functions.

Lojban encodes all 16 using the vowel (A/E/I/O/U) plus optional na (negate first) and nai (negate second). The core four vowels:

The others are derived by negating one or both inputs:

In practice, the most used are A (or), E (and), O (iff), and naA (if-then). The others arise in careful logical writing.

How nonstandard truth functions are spelled: The same na / nai recipe applies everywhere — ijek, jek, ek, gek, etc. na before the connective core negates the first piece; nai after the vowel negates the second. So .inaja = if-then; .ijanai = A or not-B; .inaje = not-A and B; .jenai = A and-not-B. The tables above name the 16 functions; the morphology is uniform once you know the base vowel (A/E/O/U).

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Tenses and Logical Connectives#

Chapter 8 gives bare .ije / gi'e; this section is about where tense and modals sit when they scope the connection itself.

Two bridi, sequential: put the tense (or modal) between the connective and bo (or tu'e):

mi viska pa nanmu .ije babo mi viska pa ninmu I see a man, and [later] I see a woman.

Here ba between .ije and bo says the second bridi is after the first (relative time), while pu on each bridi can still anchor both to the speaker’s past if you add it.

Forethought with one tense on the whole compound: a tense before ge … gi can apply to both tails at once:

mi pu ge klama le zarci gi tervecnu lo cidja I, in the past, both went to the market and bought food. (both events past; order between them not specified)

That differs from .ije babo, which asserts an explicit later-than relation between the two.

Modals + connectives: mixed BAI + .ije (e.g. .ijeki'ubo) — Chapter 10. Full CLL-style rules (ek + bo, gihek + bo, mekso parallels) are in CLL Ch.14 § “Tenses, modals, and logical connection”.

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Summary#

Forethought connectives:

• ge…gi (both), ga…gi (or), go…gi (iff), ganai…gi (if-then)
• Add forethought guheks inside selbri: gu'e…gi

Giheks (bridi-tail connectives, shared x₁):

• gi'e (and), gi'a (or), gi'o (iff), gi'enai (but not)

Full ZAhO aspect system:

• pu'o (about to), co'a (starts), ca'o (ongoing), co'u (stops), mo'u (completes), za'o (goes on too long), ba'o (resultant state), co'i (whole event)

Habitual/iterative:

• na'o (typically), ta'e (habitually), ru'i (continuously)

Tense bookmark:

• puki / caki / baki — sets reference point for subsequent bridi

Termsets (nu'i … nu'u):

• Connect multiple sumti in parallel across two bridi
• Ensure logical connective applies to all listed sumti simultaneously

All 16 truth functions:

• Built from 4 vowels (A/E/O/U) + optional na (negate first) and nai (negate second)
• Most useful: A (or), E (and), O (iff), naA (if-then = A implies B)

Tense + connective stacking:

• .ije babo — tense (e.g. ba) between .ije and bo relates the two bridi in time
• pu ge … gi — one leading tense can apply to both forethought-connected bridi
• Plain .ije with a tense on each bridi — often the clearest
• Mixed modal + .ije — Ch.10 .ijeki'ubo etc.

Nonstandard truth functions:

• Build with na / nai on the same vowel skeleton as Ch.8 — see How nonstandard truth functions are spelled above

Chapter 17. Text Structure & Quotation#

Sentence Separators: .i#

In written and spoken Lojban, sentences are separated by .i (a pause + the vowel i). Unlike an English period, .i appears between sentences — not after the last one:

mi klama le zarci .i do cadzu le bisli I go to the store. You walk on the ice.

.i implies the sentences are on the same topic or in sequence. The relationship is left vague unless you add a connective directly after .i:

mi klama le zarci .ije do cadzu — I go to the store, and you walk. mi klama le zarci .ini'ibo do cadzu — I go to the store; therefore you walk.

.ibo after .i signals the next sentence is more tightly grouped with the previous one than normal.

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Paragraphs: ni'o and no'i#

ni'o — new topic / paragraph break

Signals a topic change. Multiple ni'o cmavo in a row indicate a larger-scale shift.

no'i — resume previous topic

Like "getting back to the point…" in English. Resumes the topic in effect before the last ni'o.

ni'o la .teris. cu klama le barda tcadu (New topic:) Terry goes to the big city.

In writing: one ni'o = minor topic shift; ni'oni'o = major shift (also cancels assigned pronouns); ni'oni'oni'o = drastic reset (also resets tenses and indicators).

da'o explicitly cancels all current pronoun assignments (ko'a, ko'e, etc.) without changing the topic.

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Topic-Comment Sentences: zo'u#

zo'u separates a topic (a sumti) from a comment (a bridi). This is like Chinese topic-comment structure:

le nuzba zo'u mi ba'o djuno The news: I already know. → I already know the news.

le finpe zo'u citka The fish: eat (ambiguous — is the fish eating, or being eaten? Left vague)

zo'u is also used to introduce quantifier prenexes in logic (see Chapter 16):

ro da poi prenu zo'u da morsi For all X that are persons: X dies. → All people die.

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Quotation#

Lojban has several distinct quotation types, each with different properties:

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lu … li'u — Direct Quotation of Lojban Text#

lu opens a quotation of grammatical Lojban; li'u closes it. The contents are treated as a sumti (the quoted text itself):

la .alis. cusku lu mi klama le zarci li'u Alice says "I go to the store."

The pronouns inside lu…li'u refer to the speaker of the quotation, not the outer speaker. So mi inside quotes refers to Alice.

li'u is elidable at the end of a bridi but usually kept for clarity.

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lo'u … le'u — Error/Out-of-Context Quotation#

When quoting something that may not be grammatical or that you want to mark as questionable:

lo'u mi pu le'u cu se cusku la .djan. "mi pu" [fragment] was said by John.

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zo — Single-Word Quotation#

zo quotes the next single word as a word (not its meaning):

zo klama cu gismu "klama" is a gismu.

zo coi cu cmavo "coi" is a cmavo.

zo works for any single Lojban word, including cmavo. It cannot quote multiple words — use lu…li'u for that.

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zoi — Foreign-Language Quotation#

zoi quotes text from another language (or any arbitrary string). The syntax uses a delimiter word that appears on both sides and must not appear in the quoted text:

zoi gy. Hello World .gy. "Hello World" (in English)

mi cusku zoi gy. I love Lojban .gy. I say "I love Lojban."

The delimiter (here gy.) can be any Lojban word that doesn't appear in the text being quoted. gy. (the letter G) is conventional for English text.

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la'o — Foreign Name as Sumti#

la'o uses the same delimiter mechanism as zoi but creates a name sumti from a foreign word:

la'o gy. Aristotle .gy. cu se cusku ro nimcli Aristotle is quoted by every philosopher.

This is the correct way to use actual foreign proper names in Lojban without Lojbanizing them.

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me and me'u: Sumti-to-Selbri Conversion#

me turns any sumti into a selbri meaning "is a member of the set described by [sumti]":

ta me le'o That is a lion-like thing. (me le'o = is of the type described by le'o)

le karce cu me lo bloti The car is a boat-type thing. (it functions like a boat)

me'u terminates the me construction (elidable at end of selbri).

This lets you use descriptions, names, and other sumti as predicate words, bridging the divide between sumti and selbri.

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pe'a: Metaphorical Use Marker#

pe'a marks a word as being used metaphorically rather than literally:

mi pe'a klama le skami I metaphorically go to the computer. → I log in / I access the computer.

It signals "I know this isn't literally true — take it as a metaphor or extension."

ji'a (also) and si'a (similarly) are related discourse markers:

ji'a — in addition, also (additive)

mi klama .i ji'a do klama I go. Also, you go.

si'a — similarly

mi klama .i si'a do I go. Similarly, you [go].

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LAhE: Sumti Qualifiers#

LAhE cmavo wrap a sumti and change what it refers to — they shift reference between a thing, its symbol, and its containing set or mass.

la'e and lu'e are reverse operations — one goes from symbol to referent, the other from referent to symbol:

zo .bab. cmene la'e zo .bab. The word "Bob" is the name of the referent of "Bob". (the actual person Bob)

lu'e la .bab. cmene la .bab. A symbol for Bob is the name of Bob.

tu'a is practically very common — it lets you say "I want something to do with X" without specifying exactly what:

mi djica tu'a le plise I want something involving the apple. (I want to eat it / have it / something)

mi djica tu'a do I desire something involving you. (deliberately vague about what exactly)

Without tu'a, you'd need a full abstraction: mi djica le nu mi citka le plise. With tu'a you can stay economical.

lu'a, lu'i, lu'o, vu'i convert between different ways of grouping referents:

mi tavla lu'a le gunma I talked to a member of the group. (not the whole group)

mi viska lu'i le'i prenu I see the set of people. (as a mathematical set, not just the people)

lu'o mi'a klama We (as a mass) go. (the mass acts together)

All LAhE cmavo terminate with lu'u (elidable in most contexts):

mi nelci la'e lu'u le cukta = mi nelci la'e le cukta

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BAhE: Emphasis and Nonce Words#

ba'e stresses the next word, like spoken emphasis or written italics. It marks that the following word is the most important part of what's being said:

mi viska ba'e la .djonz. I saw Jones. (not someone else)

ba'e mi viska la .djonz. I saw Jones. (not someone else)

mi ba'e viska la .djonz. I saw Jones. (as opposed to hearing about him)

za'e marks the next word as a nonce coinage — an on-the-spot, ad-hoc word the speaker is inventing for local use, which may not exist in the dictionary:

mi klama la za'e .albeinias. I go to so-called "Albania". (nonce Lojbanization of a foreign name)

le za'e smacu'i cu zvati le zdani The so-called "mouse-neutral-thing" is in the house. (speaker is coining smacu'i on the spot)

za'e is a courtesy to the listener — it says "I know this isn't a standard word, I'm making it up as I go."

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MAI: Utterance Ordinals#

mai and mo'o turn numbers into ordinal free modifiers — firstly, secondly, lastly, etc. They can appear anywhere in an utterance:

pamai mi klama le zarci Firstly, I go to the store.

remai mi viska le mlatu Secondly, I see the cat.

romai mi sipna Lastly / finally, I sleep. (ro = all/every → "all-thly" = lastly)

Any number can precede mai: cimai = thirdly, vomai = fourthly, etc.

mo'o works the same way but marks higher-level sections (chapters, major divisions) rather than list items:

pamo'o = Section 1 / Chapter 1 remo'o = Section 2

You can combine them: pamo'o pamai = Chapter 1, point 1.

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FUhE / FUhO: Attitudinal Scope#

Normally an attitudinal applies to one word — the word immediately before it (or the whole utterance if at the start). But fu'e and fu'o let you explicitly control scope over a longer span:

fu'e opens an attitudinal scope — the attitudinal applies to everything until fu'o closes it:

mi viska le fu'e .ia blanu zdani fu'o ponse I see the owner of what-I-believe-to-be a blue house.

Here .ia (belief) applies to blanu zdani (blue house) but not to ponse (owner), because fu'o closes the scope before ponse.

Without fu'e/fu'o, .ia would attach to whatever single word it follows. This is usually sufficient, but for complex descriptions spanning many words, the scope markers give you precise control.

fu'e with an attitudinal at sentence start applies that attitudinal to all following sentences until fu'o:

fu'e .ui mi klama le zarci .i mi facki lo cukta fu'o [Happiness scope:] I go to the store. I find a book. [End happiness scope.]

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Parentheticals: to/toi, to'i, and sei/se'u#

These three constructs all insert material that is "outside" the main claim — but they work very differently.

to … toi — Spoken Parentheses#

to opens a parenthetical aside; toi closes it. The content inside can be any text and is structurally invisible to the outer parse:

mi klama to la .djan. pu cusku ke'u toi le zarci I go (John had said this before) to the store.

mi to .ui toi klama le zarci I (yay!) go to the store. (the .ui is parenthesized for emphasis)

to'i marks an editorial or quoted parenthetical — the content was not said by the current speaker (it's someone else's words or an inserted comment):

mi prami do to'i se cusku la .djan. toi "I love you" (said John, according to the text).

sei … se'u — Metalinguistic Commentary#

sei opens a sub-bridi that comments on the discourse itself — on the act of speaking, not on external facts. The sub-bridi inside sei is a full grammatical bridi but does not affect the truth conditions of the outer sentence:

mi citka sei mi cusku se'u vau le plise I eat (I say again) the apple.

le se'i bridi conventionally fills x₂ of the sei-bridi's selbri — the sentence being commented on.

Why sei/se'u exists (grammar perspective): The parser needs a way to embed a bridi inside a bridi without the inner bridi's sumti being confused with the outer bridi's sumti. sei acts as a bracket that says "parse this as a free modifier sub-bridi, not as a continuation of the main clause." se'u closes it explicitly; it can be elided before .i or vau.

Common uses:

sei mi jinvi = in my view / according to my opinion (sei-bridi = "I opine") sei se cusku = as is said / as stated (standard formula)

Comparing the three:

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SI / SA / SU: Metalinguistic Erasers#

These cmavo are used in spoken Lojban (and informal writing) to correct mistakes on the fly:

mi klama si cadzu le zarci I go— I mean walk to the store.

mi pu klama sa mi ca cadzu le zarci I went— [erase] I am now walking to the store.

si is like a backspace key; sa is like erasing a whole phrase; su is "never mind, starting over."

These have no grammatical role in the text — they are metalinguistic operations on the stream of words. They are most useful in real-time speech but can appear in written texts to represent speech authentically.

Note: si erases only the single preceding word, not any free modifiers or indicators attached to it.

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pau: Question Pre-Marker#

pau before a sentence marks it as a question even before the question word appears:

pau xu do klama Is it the case that you go? (pau = "I'm asking...")

Normally xu already signals a question, but pau makes the questioning intent explicit from the start — useful in spoken Lojban where you want to signal "this is a question" early.

paunai marks a rhetorical question — one that looks like a question but isn't:

paunai ma zmadu le ka certu mi [Rhetorical:] Who is more expert than me? (nobody, obviously)

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Hesitation: .y.#

.y. (selma'o Y) is Lojban's formal hesitation sound — the equivalent of English "uh" or "er". It requires pauses on both sides and can be held or repeated as long as needed:

mi klama .y. le zarci I go... uh... to the store.

Unlike a pause, .y. explicitly signals you still have the floor. It is not grammatical in the middle of a word but may appear anywhere else — including between sumti, after connectives, or mid-tanru.

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fa'o: End of Text#

fa'o (selma'o FAhO) explicitly marks the end of a text. It is almost always omitted but exists for contexts where an unambiguous end-signal matters:

• In computer interaction, to signal end-of-input/output
• In conversations, to explicitly yield the floor
• In written text, to mark an unambiguous stop point

fa'o is outside the regular grammar — the parser stops unconditionally when it encounters it (unless quoted with zo or lo'u…le'u). It cannot appear inside lu…li'u quotations or to…toi parentheticals.

mi klama le zarci fa'o I go to the store. [End of text]

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cmavo Interaction Rules#

Several structural cmavo affect parsing at a level before normal grammar is applied. Key rules:

• zo quotes the immediately following word, no matter what it is — even si, fa'o, another zo, etc.
• si erases the preceding word (but not if that word is zo)
• sa erases the preceding word and the current grammatical construct it belongs to
• su erases the entire current utterance
• lo'u … le'u quotes all words between them literally (including most special cmavo)
• zei combines the preceding and following word into a lujvo, but cannot combine zo, si, sa, su, lo'u, ZOI, fa'o, or another zei
• BAhE (ba'e, za'e) marks the following word — unless that word is si/sa/su or follows zo
• bu converts the preceding word into a letter word (lerfu) — cannot combine with zo, si, sa, su, lo'u, ZOI, fa'o, zei, BAhE, or another bu
• UI/CAI mark the preceding word — except zo, si, sa, su, lo'u, ZOI, fa'o, zei, BAhE, bu; a following nai is absorbed into the UI
• .y., da'o, fu'e, fu'o behave like UI but do not absorb a following nai

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Elidable Terminators#

Every construction that opens in Lojban has a corresponding terminator cmavo. Most are elidable — omittable when unambiguous. The full list:

When must you keep the terminator?

Elision is legal only when the parser can determine unambiguously where the construction ends. The main cases where you must keep the terminator:

• ke'e in mid-tanru (if more tanru follow the group)
• kei when an abstraction's x₂ follows (e.g., le su'u … kei be lo fasnu)
• ku before a selbri whose first word looks like a sumti-following word
• vau in compound bridi with tail-terms (gi'e…vau do)
• fe'u before a non-logical connective immediately after a fi'o-modal

In practice, most speech and writing elides nearly all terminators. The rule is: if elision causes ambiguity, keep the terminator.

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MAI: Ordinal Discourse Markers#

MAI cmavo (selma'o MAI) attach to a number to create discourse ordinals — words that signal position in a sequence of points or topics. They are attitudinal-like: they color the sentence they begin without contributing to the bridi's truth conditions.

pamai mi djuno lo du'u tcima ba carvi First, I know it will rain.

remai le pa'o cu spofu Second, the umbrella is broken.

romai mi ba xabju le zdani Finally, I will stay home.

MAI always attaches directly to a preceding number (no space in speech): pamai, remai, cimai. The number and mai form a single cmavo-like unit.

romai specifically means "last in this series" — not "always" or "every time." It marks the final item without specifying how many items there were total.

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MO'O: Section and Chapter Ordinals#

Where MAI marks items in a list, MO'O (selma'o MOhO) marks larger structural divisions — sections, chapters, stanzas, or other named divisions of a text:

pamo'o le cmene be le lojbo Section 1: The Name of Lojban

remo'o le gismu Section 2: The Root Words

MO'O differs from MAI in that it names a section heading — it typically appears at the start of a major structural block, not in the middle of argument:

• MAI = "this point is first/second in my argument"
• MO'O = "this block of text is section 1/2 of the overall document"

Both MAI and MO'O can be combined with the xi subscript for nested numbering:

pamo'o xi re = Section 1.2 remo'o xi pa = Section 2.1 pamai xi ci = point 1.3 in a nested list

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xi: Subscript Rules (Text Structure Context)#

xi (selma'o XI) attaches a subscript to the preceding word. It is used throughout Lojban — on pro-sumti, letters, number words, and discourse markers. Key rules for text structure:

1. xi always follows the word it subscripts: ko'a xi re = ko'a₂
2. The subscript can be a number: da xi mu = x₅
3. The subscript can be a letter string: ko'a xi by. = ko'aᵦ
4. Subscripts nest via xi chains: ko'a xi pa xi re = ko'a₁.₂
5. xi can extend any finite series: fa xi xa = the 6th place tag; ni'o xi re = second-level topic shift

For text structure, the most common uses are:

• Nested sections: pamo'o xi re = §1.2
• Nested list items: remai xi ci = item 2.3

Same cmavo elsewhere: xi also tags extra FA places (fa xi xa), logical variables (da xi re in Chapter 21), and math or letter variables (xy. xi pa in Chapter 18). For a survey of “what can be subscripted,” see the xi (subscript) section in Chapter 18 (math variables) and Chapter 21 (logical variables).

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Questions & answers: one protocol (hub)#

Questions and answers are spread across several chapters of this book. Friendly chapters spread the pedagogy (Chapter 6 — content questions; Chapter 8 — connective questions; Chapter 7 — pei; Chapter 13 — na / ja'a answers). This subsection is the single roadmap: question devices, what you may answer with, and where to read the lessons.

Fill-in-the-blank questions place a question cmavo where the answer would go. The answer often need not be a full bridi — it completes the open claim of the question (see the question/answer table below).

Parallel questions with fa'u: Chapter 8 explains fa'u (“respectively”) for statements. The same pattern pairs ma slots:

ma fa'u ma klama ma fa'u ma Who and who goes where and where, respectively?

la .djan. fa'u la .marcas. le zarci fa'u le briju John and Marsha [go] to the store and to the office, respectively.

Answers may be grammatical without repeating the whole bridi. Mechanical substitution of answer into question can look odd until elided terminators are mentally restored — the elision rules are covered in Chapter 21.

Kinds of non-bridi answer (not an exhaustive list): one or more sumti; a bare connective; a number or parenthesized mekso; na or ja'a; a relative clause hanging on a prior sumti; a prenex; be/bei linked to a prior selbri; at the start of a text, bare names, indicators, or vague nai. See the table above and the chapters on negation, connectives, and logic.

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Summary#

Sentence / text structure:

• .i = sentence separator (between sentences)
• ni'o = new topic; no'i = resume old topic
• zo'u = topic-comment separator; also introduces quantifier prenex
• da'o = cancel pronoun assignments

Quotation types:

• lu … li'u = direct Lojban quote
• zo = single-word quote
• zoi gy. … .gy. = foreign text quote
• lo'u … le'u = error/fragment quote
• la'o gy. … .gy. = foreign name as sumti

Sumti qualifiers (LAhE):

• la'e = referent of; lu'e = symbol for
• tu'a = something involving (vague event); lu'a = a member of
• lu'i = the set of; lu'o = the mass of; vu'i = the sequence of

Emphasis and nonce:

• ba'e = emphasize next word; za'e = nonce coinage

Ordering:

• pamai/remai/romai = firstly/secondly/lastly; pamo'o/remo'o = section 1/2

Attitudinal scope:

• fu'e = open scope; fu'o = close scope

Parentheticals and metalinguistics:

• to … toi = spoken parentheses (any content, invisible to parser)
• to'i … toi = editorial/quoted parenthesis
• sei … se'u = metalinguistic sub-bridi (grammatical bridi, comments on discourse)

Self-correction (erasers):

• si = erase previous word; sa = erase current construct; su = erase utterance

Other:

• me … me'u = sumti-to-selbri conversion
• pe'a = metaphorical use marker
• pau = question pre-marker (nai = rhetorical question)

Questions & answers (hub):

• One table + ma fa'u ma example + non-bridi list — see Questions & answers: one protocol (hub) above; detail in Ch.6 / Ch.8 / Ch.13

Hesitation and end-of-text:

• .y. = formal hesitation sound (holds the floor; requires pauses on both sides; can be dragged out)
• fa'o = explicit end of text (outside regular grammar; parser stops unconditionally)

cmavo interaction priorities (processed before normal grammar):

• zo quotes the immediately following word unconditionally
• si/sa/su erase; lo'u…le'u quotes literally; zei compounds two words into lujvo
• BAhE marks following word; bu converts preceding word to lerfu; UI/CAI mark preceding word
• .y., da'o, fu'e, fu'o behave like UI but do not absorb a following nai

Elidable terminators (full list):

• be'o (BE), boi (PA/BY), do'u (COI/DOI), fe'u (FIhO), ge'u (GOI)
• kei (NU), ke'e (KE), ku (LE/LA), ku'e (PEhO), ku'o (NOI)
• li'u (LU), lo'o (LI), lu'u (LAhE), me'u (ME), nu'u (NUhI)
• se'u (SEI), te'u (mekso), toi (TO), tu'u (TUhE), vau (bridi), ve'o (VEI)
• Keep terminator when elision is ambiguous; kei be = must keep before abstractor x₂

Chapter 18. Letters, Numbers & Math#

The Lojban Alphabet: lerfu#

Each letter of the Lojban alphabet has a name — a cmavo of selma'o BY. These are used to spell words, give initials, or refer to letters as objects.

Vowel letters:

Consonant letters follow the pattern Cy (consonant + y):

Apostrophe is named .y'y. and period/pause is .denpa bu.

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Spelling Words#

To spell a word, list its lerfu in sequence:

zo lojban cu se lerfu ly. .obu jy. by. .abu ny. "lojban" is spelled l-o-j-b-a-n.

Letter strings can be used as sumti directly: ly. .obu jy. by. .abu ny. = "lojban" (as a string of letters).

bu is a cmavo that turns any Lojban word into its letter name:

la .alis. bu — the letter/symbol "Alice" (Alice used as a symbol) lo skami bu — the symbol "skami"

This is how arbitrary symbols and single-character names are created on the fly.

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Numbers: PA cmavo#

The ten digits are single cmavo:

Numbers are written by concatenating digits left-to-right (most significant first):

parebici = 1283 rezevomu = 2745

Two-digit values work the same way: pa no = 10, pa pa = 11, ci mu = 35.

Special number words:

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Number Bases and Fractions#

pi is the decimal point:

ci pi vo = 3.4 pamu = 0.5 (half)

Numbers as selbri (PA as brivla-like): a number alone acts as a quantifier or a predicate:

le ci gerku = the three dogs mi ci = I am three (I am the third) pa le gerku cu blabi = one of the dogs is white

fi'u = fraction separator:

pa fi'u re = 1/2 ci fi'u vo = 3/4

ma'u / ni'u = positive / negative sign:

ni'u re = −2 ma'u mu = +5

Mathematical constants (PA cmavo standing alone):

li pai su'i te'o = π + e

ki'o = comma separator (thousands):

pa ki'o = 1,000 re ki'o vo no no = 2,400

ce'i = percent sign (follows the number):

ci mu ce'i = 35% pamu ce'i = 50%

ka'o = imaginary-unit separator for complex numbers:

ci ka'o re = 3+2i (three plus two-i) ni'u pa ka'o vo = −1+4i

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Ordinal Numbers#

Place moi after a number to get an ordinal:

pamoi = first remoi = second cimoi = third

mi pamoi klama = I am the first to go. le remoi prenu = the second person

mei makes a number into "a set/group of N":

le ci mei = the trio / the group of three

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Math: mekso#

Lojban has a full mathematical expression system called mekso ("mathematical expression"). It is designed to be unambiguous — operator position, parentheses, and precedence are all explicit.

li — Math Expressions as Sumti#

li introduces a numeric or mathematical expression as a sumti (a number-as-object):

li ci su'i vo du li ze The number (3 + 4) equals the number 7.

du = equals (mathematical identity). The whole mekso expression follows li.

Operator Order#

Mekso supports two operator positions:

Infix (operator between operands) — most natural for simple expressions:

li re su'i ci = 2 + 3 = 5 li mu vu'u re = 5 − 2 = 3 li re pi'i ci = 2 × 3 = 6

Polish / forethought (operator before operands) — unambiguous for nested expressions:

li su'i re ci = +(2, 3) = 5

In practice, infix is most common for simple arithmetic. For complex nested expressions, vei…ve'o parentheses make infix equally unambiguous.

vei … ve'o — Parentheses in Mekso#

vei opens a parenthesized sub-expression; ve'o closes it:

li vei re su'i ci ve'o pi'i vo du li re no (2 + 3) × 4 = 20

Without vei, bi'e, or a ti'o precedence declaration, infix VUhU operators group left to right (like a simple calculator) — not automatic “multiplication before addition” . So li re su'i ci pi'i vo means ((2 + 3) × 4) = 20, not 14.

li re su'i vei ci pi'i vo ve'o — 2 + (3 × 4) = 14

Explicit vei/ve'o stays the clearest fix; bi'e (below) is the compact alternative.

bi'e — higher-precedence operators (compact infix)#

Prefix bi'e to a VUhU operator (selma'o BIhE) so that operator binds before neighbors that lack bi'e — the standard Lojban way to get “multiply before add” on one line:

li ci su'i vo bi'e pi'i mu du li reci 3 + (4 × 5) = 23

If several operators carry bi'e, grouping is from the right; bi'e bi'e on a single operator is not allowed. When a formula gets busy, prefer vei … ve'o or split across sentences.

Logical connectives within mekso#

Operands and operators follow the same connective classes as ordinary language: sumti-style eks (.e, .a, …) between operands, jeks (je, ja, …) between VUhU operators (Chapter 8). A few consequences:

• Quantifiers often wrap mekso in vei … ve'o when the number is not a single PA:

vei ci .a vo ve'o prenu cu klama le zarci Three or four people go to the market.

• lo'o closes li when the next connective belongs to the outer sentence, not to the mekso:

li re su'i re du lo'o .ije … Two plus two equals …, and …

• Operators can be joined (contrived but grammatical):

li re su'i je pi'i re du li vo Two [plus and times] two equals four. (parallel to su'i je pi'i as a connected operator cluster)

CLL has full tables for operand/operator connection and for ke-grouping of operators; for textbook prose, prefer explicit vei/ve'o and separate sentences until you need this density.

Full VUhU Operator Table#

VUhU operators are used in mekso (mathematical expressions). They work in infix (between operands) or in Polish/forethought notation (before operands).

Unary operators take one operand; binary take two. When used as VUhU in Polish notation, the operand count must be satisfied: su'i re ci = +(2,3) = 5 (binary, both operands follow).

The boi separator distinguishes multiple operands when two numbers would otherwise run together:

de'o re boi bi = log base 2 of 8 (boi separates the base "re" from the argument "bi")

Special Number Words in Detail#

Beyond simple digits, the PA cmavo include several "fuzzy" quantity words:

ji'i panono prenu pu klama Approximately 100 people came.

za'u re nanmu cu zvati More than two men are present.

me'o introduces a numeral as a symbol (not evaluated as a quantity):

me'o xy. = the symbol x (as a variable name, not a number) me'o paremubi = the string "1-2-8" as a symbolic label

na'u and ni'e: Connecting Mekso with Selbri#

na'u converts a VUhU operator into a selbri usable in a regular Lojban bridi. The resulting selbri has the place structure of the underlying mathematical relation.

Worked example — na'u su'i (addition as selbri):

The VUhU su'i (addition) has the implicit place structure:

• x₁ = the sum
• x₂ = one addend
• x₃ = the other addend

When promoted to selbri via na'u:

li mu na'u su'i re ci 5 is the sum of 2 and 3. Literally: 5 [is-x₁-of addition] 2 3

li re na'u su'i ci du li mu 2 + 3 = 5 (using du = "equals" to close the equation)

You can use SE conversion on na'u-selbri:

li re na'u se su'i mu 2 is an addend summing to 5 (se shifts x₁↔x₂: now x₁ is an addend, x₂ is the sum)

Another example — na'u pi'i (multiplication as selbri):

li xa na'u pi'i re ci 6 is the product of 2 and 3.

la meris. cu se zmadu la .alis. lo ka barda Mary exceeds Alice in bigness. (non-mekso parallel)

The power of na'u is that it lets you make claims about mathematical relationships using the full Lojban logical and quantifier system:

ro da poi kacna'u zo'u su'o de poi kacna'u zo'u da na'u su'i de du li no For every integer, there is some integer whose sum with it equals zero. (additive inverses)

ni'e converts a selbri into a mekso operand — the selbri's x₁ determines the numeric value:

li ni'e melbi pi'i re The beauty-value times two (treating "beauty" as a numeric measure)

mo'e converts any sumti (often a ni abstraction) into a mekso operand:

li mo'e le ni le pixra cu blanu the number representing how blue the picture is

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MOI: Quantifier Selbri#

moi and mei turn numbers into selbri. The full MOI series:

mi pamoi klama = I am the first to go. le remoi prenu = the second person. le pimu si'e le plise cu fusra = Half the apple is rotten. le nu carvi cu pano cu'o = There is a 10% probability of rain. do vo va'e certu = You are a level-4 expert.

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Subscripts: xi#

xi attaches a subscript (a number or letter string) to almost any word:

ko'a xi pa = ko'a₁; ko'a xi re = ko'a₂ fa xi xa = the 6th place tag (extending beyond the standard fa/fe/fi/fo/fu) da xi vo = x₄ (logical variable with subscript)

Subscripts allow infinite extension of any finite cmavo series. They are particularly useful for:

• Extending logical variables: da xi pa, da xi re, da xi ci = x₁, x₂, x₃
• Tracking multiple discourse referents: ko'a xi pa = "the first one", ko'a xi re = "the second one"
• Math variables: xy. xi pa = x₁ (the symbol x subscript 1)

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Spelling and Letterals in Depth#

bu: The Universal Letter-Maker#

bu following any Lojban word converts it to a lerfu (a letter or symbol) representing that word:

zo coi bu = the symbol "coi" (the word coi treated as a single glyph/symbol) la bu = the symbol "la" mi bu = the symbol "mi" (useful for algebra-like notation)

This lets you create symbols for any concept on the fly.

Letterals as Pro-Sumti#

Outside math contexts, lerfu strings (like .abu, xy.) act as a second set of assignable pronouns alongside ko'a…ko'u:

.abu cu klama — .abu goes (tracking a referent) xy. du li re — x = 2 (math variable) da xi pa zo'u xy. xi pa du da xi pa — x₁ = da₁ (linking symbolic to logical)

This extends the Lojban pronoun system almost without limit.

Upper and Lower Case: ga'e, to'a, tau#

Lojban does not capitalize sentences or names. Capital letters only appear inside Lojbanized names to mark irregular stress (e.g., .iVAN.). To spell out names with capital letters, use the shift words:

ga'e and to'a are persistent — they stay in effect until contradicted:

.ibu ga'e vy. .abu ny. to'a i V A N (the name "Ivan" with Russian capitals)

tau shifts only one letter, then reverts. Useful for chemical element symbols:

tau sy. = S (upper-case S = sulfur symbol) tau sy. .ibu = Si (silicon: upper S then lower i)

If a global upper-case shift (ga'e) is active, tau reverses it for that one letter (producing lower case).

Compound Letterals: tei … foi#

tei and foi create a compound lerfu — multiple letters treated as a single, indivisible symbol:

tei xy. ny. foi = the compound symbol "xn" (treated as one unit) tei .abu xy. foi = the symbol "ax"

This is needed when a lerfu string should be interpreted as a single symbol rather than separate letters in sequence. Useful for creating multi-character variable names.

tei/foi are also essential for accent marks in foreign words. Accent marks have their own lerfu words, but the ordering (mark before or after the base letter?) is language-specific. tei…foi removes the ambiguity by grouping base + mark into one unit:

tei .ebu .akut.bu foi ty. tei .akut.bu .ebu foi (é) t (é) — spells French été unambiguously

The acute accent is .akut.bu (the name akut. + bu). It doesn't matter whether it comes before or after .ebu inside the tei…foi brackets — the grouping guarantees association.

Similarly, tei handles multi-letter digraphs that some languages treat as single letters:

tei ly. ly. foi = the Spanish ll (a single letter in traditional Spanish)

me'o: Referring to the Letter Itself#

When a lerfu string appears in running Lojban text, it acts as a pro-sumti (a pronoun — see Letterals as Pro-Sumti above). This means .abu is interpreted as "the thing previously assigned to .abu", not as a reference to the letter a.

To refer to the letter itself — to say "a is a letteral" — use me'o:

.abu cu lerfu ✗ — attempts to find a previous referent named .abu me'o .abu cu lerfu ✓ — The expression "a" is a letter.

me'o (selma'o LI) is the "mathematical expression" introducer. It signals: treat what follows as the symbol itself, not as a reference to what the symbol denotes.

me'o xy. cu se lerfu la .alis. The letter "x" is used in Alice's name.

dei vasru vo lerfu poi me'o .ebu This sentence contains four instances of the letter "e".

Contrast with quoting:

Spelling Words Aloud#

To spell a word letter by letter:

la .alis. cu se lerfu .abu ly. .ibu sy. "Alice" is spelled a-l-i-s. (simplified spelling)

To assemble letters back into a word, use lu'o (mass of) to collect the lerfu into a single word-object:

lu'o .aby ly .ibu sy. du zo alis a+l+i+s = "alis" (the mass of these letters equals the word alis)

Quoting Rafsi and Non-Words#

lo'u…le'u quotes non-grammatical strings. For rafsi and morphological fragments:

lo'u kla le'u = the rafsi "kla" (for klama) lo'u -alis- le'u = the fragment "-alis-" as a string

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Counting and Measurement#

la'u + number = measurement tag (how much):

la'u li mu = for a quantity of five / by fives

Comparisons are clearest with zmadu / mleca and a ka property (see Chapter 14); mau / me'a as BAI tags often want se conversion in real text.

mi zmadu do le ka barda I am bigger than you.

le zarci cu mleca le zdani le ka barda The store is smaller than the house (in size).

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Forethought Operators: Polish Notation in mekso#

Standard mekso uses infix operators (between operands). Lojban also supports forethought (Polish notation) where the operator comes first, before its operands. This is marked by pe'o:

pe'o su'i ci vo = +(3, 4) = 7

li pe'o su'i ci vo du li ze 3 + 4 = 7 (Polish form)

Forethought is more explicit and unambiguous because the operator comes first and the operands follow in order. It's closer to function notation:

pe'o pi'i re ci vo = ×(2, 3, 4) = 24 (three-argument multiplication)

The ku'e terminator closes a forethought expression when there could be ambiguity about how many operands were taken.

Forethought in complex expressions:

pe'o su'i pe'o pi'i re ci pe'o pi'i vo mu = +(×(2,3), ×(4,5)) = 6 + 20 = 26

No parentheses needed — the nesting is unambiguous because each pe'o expression takes exactly as many operands as the operator requires.

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Non-Decimal Bases#

By default, Lojban numbers are base 10. To express a numeral string in another base, use the VUhU operator ju'u between the number-in-that-base and the base (see the Bases section in this chapter above for full detail). Digits pa through so still mean 1–9; bases above 10 use extra digit cmavo (dau, fei, …).

li panopano ju'u re du li pano The number [written] 1010 in base 2 equals [decimal] 10.

li daufeigai ju'u paxa du li rezevobi The number [written] ABC in base 16 equals [decimal] 2748.

Only digit values valid in the chosen base may appear on the left of ju'u (e.g. do not use re as a digit in base 2).

ra'o (selma'o RAhO) flags a GOhA pro-bridi so that pro-assignments inside the copied bridi are updated for the new context — the standard device for “viewpoint shift” in indirect speech, not a general pronoun reset (use da'o for assignable sumti).

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Reverse Polish Notation#

Besides prefix (forethought) and infix, mekso also supports postfix (Reverse Polish Notation / RPN), common in HP calculators and Forth:

fu'a (selma'o FUhA) marks the start of an RPN expression.

fu'a ci vo su'i = 3 4 + (the operator comes after both operands) = 7

fu'a re ci pi'i vo su'i = 2 3 × 4 + = (2×3)+4 = 10

RPN is unambiguous without parentheses when operator arity is known. It's rarely used in everyday Lojban but is provided for completeness (and for stack-machine enthusiasts).

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Mekso: vectors, indefinite numbers, precedence, and word problems#

This block lines up with places where the preceding sections have been lighter: arrays, fuzzy counts, formal precedence, and a worked “story problem.”

Vectors and matrices: jo'i, pi'a, sa'i#

A vector is a fixed list of simple operands. jo'i (selma'o JOhI) opens the list; boi separates components; te'u closes (often elidable when unambiguous):

li jo'i paboi reboi te'u su'i jo'i ciboi voboi te'u du li jo'i voboi xaboi te'u (1, 2) + (3, 4) = (4, 6).

pi'a stacks row-vectors into a matrix; sa'i stacks column-vectors. Extra rows/columns chain with the same operator (CLL uses ge'a between operands when needed). A compact 2×2:

li jo'i paboi reboi pi'a jo'i ciboi voboi The matrix with rows (1, 2) and (3, 4).

The classic 3×3 “magic square” from CLL is built the same way with three jo'i … operands joined by pi'a (or three columns joined by sa'i). When you combine matrices with other operators, wrap in vei … ve'o so grouping stays obvious.

Indefinite PA (and roi)#

Besides ji'i, za'u, me'i, su'e, su'o (already above), Lojban has so'a, so'e, so'i, so'o, so'u — five objective indefinite sizes below ro, in decreasing order (roughly: almost all → … → a few). They are still vague: so'e is not “more than half” by rule.

pi-prefixed forms (piro, piso'a, …) talk about parts of a whole (masses), not “N items out of a bag.” no'o is “the typical amount” (not necessarily a statistical mean — see CLL).

Those cmavo usually quantify sumti. Inside li, prefer explicit arithmetic, ji'i, or bounds (su'o re … su'e mu) when you need a numeric claim with slack.

Digit + roi is not a mekso operator: it builds tenses like English once, twice (e.g. pare roi, reroi) — see Chapter 9 and Chapter 21 for samples.

Explicit operator precedence (ti'o)#

CLL describes ti'o (with sei-family syntax) as a place to declare relative precedence among VUhU operators for future parsers. Current practice: default infix is left-to-right (see bi'e under Operator Order); spell school-math grouping with vei … ve'o or bi'e, or use forethought pe'o / fu'a. Do not assume readers apply “PEMDAS” unless you mark it.

nu'a — operator into selbri (inverse of na'u)#

nu'a wraps a VUhU cmavo as an ordinary selbri (inverse of na'u). One CLL-style illustration:

li ni'umu cu nu'a va'a li ma'umu −5 is the negation-as-operation applied to +5.

Together, na'u and nu'a let you answer “which operator?” questions without a dedicated operator-question cmavo (CLL §18.19).

“Four score and seven” — the number 87#

A score is 20 (like a dozen is 12). Four score and seven = 87. Several honest Lojban renderings:

li bize — plain 87 (correct, dry).

li vo pi'i reno su'i ze — four times twenty, plus seven.

li vo pi'e ze ju'u reno — digit string “4;7” read in base 20 (French quatre-vingt-sept flavor).

CLL also discusses mo'e with mei-style sumti (voboi renomei, “four twentysomes”) to mimic “four groups of twenty” before adding seven; the same pattern works in this chapter — te'u closes the mo'e expression when needed; see the Sumti as operands section above.

mai and mo'o — “firstly…”, section numbers#

mai (selma'o MAI) turns a digit string or lerfu string into a free modifier: an outline label like English firstly, secondly, nth, or lastly.

pamai — firstly  remai — secondly  romai — lastly (literally “all-thly”)

ny.mai — nth (after ny. as “n”)

mo'o is the same idea for larger chunks of structure: chapters vs paragraphs, acts vs scenes. A pasomo'o line marks a high-level slice; inside it you might still use pamai / remai for steps. Full discussion of moʻo in text structure is in Chapter 17.

Grammar note: there is no boi between the number/lerfu string and mai / roi (same rule family) — see the mai / mo'o section above in this chapter.

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bu in Depth: Any Word as a Symbol#

bu is not just for common letters — it converts any Lojban word into a symbol name. This makes it possible to use arbitrary words as single-character labels:

klama bu = the symbol "klama" (the word treated as a single letter/symbol) la .teris. bu = the symbol "T" (using the name Terry as a symbol) lo gerku bu = the symbol "dog" (used as a label)

This extends to create symbols for mathematical or logical variables using recognizable Lojban words:

prenu bu = p (person symbol) gerku bu = g (dog symbol)

And for single punctuation characters or other signs:

lidne bu = a leading-dot symbol .y'y. = the apostrophe letter name (already built in) denpa bu = the period / pause mark (already built in)

bu is also how you refer to non-Lojban scripts: you can create lerfu words for Greek letters (alfas., betas., etc. using cmene convention), Cyrillic, Hebrew, and others, by combining bu with borrowed names.

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Acronyms, character codes, punctuation, and script shifts#

Acronyms (initials as names): Glue lerfu words into a cmene: insert ' wherever two vowels would touch, and end with a consonant (often repeating the last lerfu’s consonant or tagging culture: merko, brito, …). Compression: vowel lerfu may drop bu except .y.bu. Alternative: treat the string as a predicate-name with la me:

la me dy. ny. .abu That which satisfies “d, n, a” — usable as a name DNA-style, with pauses allowed between lerfu.

se'e (BY) — computerized codes: se'e + a PA number is one character in an agreed charset (ASCII, Unicode hex with a spoken convention, …). The hearer must know the table and base.

me'o se'e cixa cu lerfu la .asycy'i'is. The expression “code 36” is a letteral in ASCII. (36 = dollar sign in ASCII)

Unicode (hex) and “big” scripts: The same se'e device works for Unicode when everyone agrees you are using hexadecimal code points and the Unicode chart — not just ASCII. For Unicode code points, spell them as digit strings with se'e acting as a base-16 prefix; for example, U+262E (peace symbol ☮) is me'o se'e rexarerei (hex digits r·e·x·a·r·e·r·e·i under the BY names: re=2, xe=6, reno=2, bi=E). For CJK or any long non-Latin passage, zoi / la'o (Chapter 17) is usually clearer than spelling glyph-by-glyph; zai + an alphabet name still switches BY strings when you need a short native letter inside Lojban prose (see zai / ce'a below in this section).

lau (LAU) — punctuation, not letters: lau must be followed by a BY word. It marks that the bu-symbol names a punctuation mark (comma, dash, …), not an alphabetic letter — important when the same shape could be read either way.

zai (LAU) / ce'a (LAU) — shifts: zai switches which alphabet following BY words belong to (Latin vs Greek, …) until cancelled. ce'a switches font or glyph style (italic, bold, …). Interpretation depends on agreed conventions.

Raw foreign text: For un-Lojbanized passages, use zoi / la'o (Chapter 17 — Text Structure & Quotation). Tone digits in pinyin-style spellings can sit inside lerfu strings: .abu ny. vo … = han⁴….

Auxiliary lerfu cmavo (roadmap): tei/foi (compound glyph); ga'e/to'a/tau (case); lau/zai/ce'a (punctuation / alphabet / font); se'e (code point); me'o/lo'o (quote expression / close li). Not every CLL corner case is needed until you typeset mixed scripts or data protocols.

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Summary#

Lerfu (letters):

• Vowels: .abu .ebu .ibu .obu .ubu ybu
• Consonants: by. cy. dy. etc.
• bu turns any word into a letter/symbol name — extends to any alphabet
• tei … foi = compound multi-character symbol (also used to group base letter + accent mark)
• se'e + PA = numeric character code (ASCII/Unicode by convention — see Unicode paragraph under Acronyms…); lau/zai/ce'a = punctuation / alphabet / font shifts on BY
• Acronyms: glue lerfu into cmene, or la me + lerfu string
• Lerfu strings outside math act as assignable pro-sumti

Case shifts:

• ga'e = shift all following lerfu to UPPER CASE (persistent until to'a)
• to'a = shift back to lower case
• tau (LAU) = single-shift: next lerfu only to upper case (or lower if ga'e active)
• Example: .ibu ga'e vy. .abu ny. to'a = i V A N

Accent marks:

• Accent marks are lerfu words (e.g. .akut.bu = acute accent)
• Use tei…foi to bind accent to its base letter unambiguously regardless of order
• tei .ebu .akut.bu foi = é (e with acute) — order within tei/foi doesn’t matter

me’o — referring to the letter itself:

• Bare lerfu strings (.abu, xy.) are pro-sumti (pronouns), not references to the letter
• me’o .abu = the letter a itself (selma’o LI; treats what follows as a symbolic expression)
• Contrast: lu .abu li’u = the word “.abu”; la’e lu .abu li’u = the referent of .abu; me’o .abu = the letter a

Numbers (PA):

• Digits: no pa re ci vo mu xa ze bi so (0–9)
• Concatenate for multi-digit: parebici = 1283
• pi = decimal point; fi'u = fraction; ni'u/ma'u = sign
• Fuzzy quantities: ji'i (approx), za'u (more than), me'i (less than), du'e (too many)

Ordinals/cardinals/fractions:

• pamoi, remoi = 1st, 2nd; pa mei = group of one
• pimu si'e = half-portion; pimu cu'o = 50% probability; ci va'e = level-3

Math (mekso):

• li = introduces a number/expression as sumti
• Logical connectives inside mekso: eks between operands, jeks between operators (Ch.8); lo'o closes li before an outer .ije (etc.)
• me'o = introduces a numeral as a symbolic label (not evaluated)
• su'i, vu'u, pi'i, fe'i, te'a = +, −, ×, ÷, ^
• ne'o = factorial; de'o = log; ge'a = absolute value; gei = scientific notation
• jo'i … te'u = vector; pi'a / sa'i = matrix from row / column vectors
• vei … ve'o = mekso parentheses
• bi'e = precedence bump on an infix VUhU (multiply-before-add style); default infix is left-to-right, not PEMDAS — see bi'e under Operator Order
• boi = operand separator
• du = mathematical equals; xi = subscript
• na'u / nu'a = operator ↔ selbri (inverse cmavo pair); ni'e = selbri → operand; mo'e = sumti → operand
• mai / mo'o = outline labels (firstly, big section numbers); see mai / mo'o under Mekso: vectors…; discourse detail in Chapter 17
• ti'o = planned precedence declarations for future parsers — meanwhile use vei/ve'o, bi'e, or forethought; default infix is left-to-right, not PEMDAS
• Indefinite PA: so'a … so'u (ordered fuzzy sizes); pi-forms for fractions of masses; roi after digits = tense, not math (Ch.9)
• pe'o = forethought (Polish) notation: operator comes first
• fu'a = reverse Polish (postfix) notation: operator comes last
• ju'u = base specifier for non-decimal numbers

Chapter 19. Phonology Deep Dive#

The Lojban Sound System#

Lojban was designed to be pronounceable by speakers of all major world languages. Its phonology is conservative: only sounds that appear across many different language families were chosen.

If English is your first language#

Spelling and sound line up, but English habits mislead unless you override them:

Diphthongs (ai ei oi au) are one syllable each — a glide ending toward /j/ or /w/, not two separate vowel letters in speech. Rough parallels: kight, day, boy, cow (accents differ; aim for a single moving vowel, not “ah-ee” as two beats).

Punctuation is phonemic: . marks a real pause (often glottal stop) before a vowel-initial word; , inside a word only disambiguates syllables (Special Characters below). There are no “silent letters” in ordinary Lojban words.

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Vowels#

Lojban has six vowels:

y is special: it's the "buffer vowel" used in lujvo and to resolve consonant clusters. It never carries stress, cannot start a word, and doesn't count when determining consonant clusters in morphology.

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Consonants#

Key pronunciation notes:

• c = /ʃ/ (English sh) — never /k/ or /s/
• j = /ʒ/ — the middle sound of measure
• x = /x/ — the back-of-throat sound, not /ks/ or /gz/
• g = always hard /g/ — never /dʒ/ as in English gem

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Voiced / Unvoiced Pairs#

Lojban consonants come in voiced/unvoiced pairs:

This pairing matters for consonant cluster rules: a voiced consonant cannot be directly adjacent to an unvoiced one (with a few exceptions: sf, zv, jv, lv, etc.) without a separating vowel.

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Special Characters#

Apostrophe (') — represents /h/ (a voiceless glottal fricative, like English h). It always appears between vowels and creates a brief breathing gap:

ta'a = /taˈha/ (roughly) — two syllables with h between ki'a = /kiˈha/ — exclamation of puzzlement

The apostrophe is required in writing wherever this /h/ sound appears. You cannot omit it.

Period (.) — represents a full stop or pause. Required before any word beginning with a vowel:

.abu (the letter a) — pause before the vowel .i — sentence separator: pause then /i/ la .alis. — pause before and after the name Alice

The period is a genuine phonological element — a glottal stop or short silence. In careful speech, every word-initial vowel is preceded by a pause.

Comma (,) — used only within words to mark a syllable break that might otherwise be ambiguous. It has no pronunciation; it is a written-only aid to parsing:

.ei,u — two separate vowels (not the diphthong ei + u), or to mark that ei and u are in separate syllables

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Diphthongs#

A diphthong is a two-vowel sequence pronounced as a single syllable (no separating consonant or apostrophe):

Four true diphthongs (falling — the first vowel is more prominent):

• ai /aj/ — like English kite
• ei /ej/ — like English day
• oi /oj/ — like English boy
• au /aw/ — like English cow

These are used in attitudinals (.ui .oi .ai .ei) and cmavo.

Vowel pairs with apostrophe are not diphthongs — the /h/ separates them into two syllables:

u'i = /uhi/ — two syllables, not a diphthong

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Stress Rules#

Lojban stress is penultimate (second-to-last syllable) for all brivla, and conventional (usually first syllable) for cmavo:

For brivla:

KLA-ma (klama) PRE-nu (prenu) BLA-nu (blanu) mel-BI — no, wrong: MEL-bi (melbi)

The stress always falls on the vowel of the second-to-last syllable. The y vowel and apostrophe are ignored when counting syllables for stress:

loj-BAN — wrong LOJ-ban — correct (lojban has 2 syllables: loj-ban, stress on first = penultimate)

For cmavo:

• No mandatory stress; conventional stress is on the first vowel
• Two-syllable cmavo like ki'a, ta'e, ca'o stress the first vowel: KI'a, TA'e, CA'o

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Syllabic Consonants#

The consonants l, m, n, and r can be syllabic — that is, they can form a syllable nucleus when surrounded by consonants, replacing what would otherwise be an uncomfortable consonant cluster:

bridi — the r is not syllabic (it has vowels on both sides) ta'onai — not syllabic prali — the r can be syllabic in some clusters

In standard pronunciation, when one of these consonants appears between two consonants with no vowel, it is pronounced with a faint schwa-like quality.

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Consonant Clusters#

Lojban allows consonant clusters, but only permissible pairs. The rules:

General permissibility test for any CC pair: A pair is permissible unless it:

• Contains two identical consonants (pp, tt, etc.)
• Mixes a voiced and unvoiced member of the same stop/fricative pair: bd, pb, dt, td, gk, kg, vf, fv, zs, sz, jc, cj
• Contains cx or xc (sibilant+velar fricative combinations)
• Contains mz, nz, nm, mn (nasal+sibilant combinations: only ns and nz are allowed)

Permissible initial clusters (full list):

Initial clusters are the stricter subset used at the start of a word or syllable (in gismu, lujvo, and fu'ivla). There are exactly 48 permissible initial pairs:

The complete 48 (in alphabetical order): bl, br, cf, ck, cl, cm, cn, cp, cr, ct, dj, dl, dm, dn, dr, dv, dz, fl, fr, gl, gn, gr, jb, jd, jg, jm, jv, kl, kr, ml, mr, pl, pr, sf, sk, sl, sm, sn, sp, sr, st, sv, tc, tr, ts, vl, vr, xl, xr, zb, zd, zg, zm, zn, zv.

These are the only clusters that may begin a word or syllable. All other combinations require a vowel (usually y) inserted between them.

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Vowel Pairs: Diphthongs vs. Apostrophe Pairs#

Two adjacent vowels in Lojban are either a diphthong (one syllable) or a VV pair (two syllables, separated by apostrophe /h/):

Diphthongs — one syllable, no apostrophe:

These four only occur in Lojban cmavo and attitudinals. Any other vowel combination in a native Lojban word requires an apostrophe to separate the syllables.

VV pairs with apostrophe — two syllables:

All other adjacent vowel combinations in native Lojban words must use an apostrophe:

• u'i, a'i, o'e, i'e, e'a, etc.
• The apostrophe represents /h/ between the vowels: u'i = /u.hi/

In names (cmene): vowel pairs without apostrophe are permitted when the source language has them. A comma may be used in writing to indicate that two vowels are in separate syllables without implying /h/ pronunciation: .ei,u = three separate sounds, no diphthong and no /h/.

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Buffer Vowel Insertion#

When Lojban requires a vowel to break up an impermissible consonant cluster (in lujvo, cmene, or fu'ivla), the buffer vowel y is used in most cases:

pante + tavla → patyta'a (not patta'a — tt is illegal) mudri + siclu → mudysiclu

The choice of buffer:

• y (schwa): standard in lujvo; it is morphologically transparent and doesn't carry stress
• i or u: used in names when y would feel unnatural or when the source language vowel is closer

In names, the buffer vowel is chosen to match the source phonology as closely as possible. The key rule is simply: every consonant pair in the result must be permissible.

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Syllabication Algorithm#

To determine where syllable breaks fall — which determines stress — Lojban uses a greedy algorithm:

1. Start from the left.
2. At each point between two consonants in a VC₁C₂V sequence: if C₁C₂ is a permissible initial cluster, the break is before C₁ (both consonants go to the next syllable: V | C₁C₂V).
3. If C₁C₂ is not a permissible initial cluster, the break is between C₁ and C₂ (VC₁ | C₂V).

Example: ta-vla — vl is a permissible initial pair → break before v → /tav.la/ — oops, that gives vl at the start of the second syllable which is correct: tav-la → stress on first syllable tav.

Example: mlatu — ml is a permissible initial pair → no break before ml, so: mla-tu → stress on mla.

Example: bridi — br is a permissible initial → bri-di → stress on bri.

Example: lojban — jb is a permissible initial → loj-ban → only 2 syllables → stress on first = LOJ-ban.

This algorithm determines which syllable is penultimate, which always receives stress in brivla.

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Audio-Visual Isomorphism#

Lojban is designed to be "audio-visual isomorphic" — what you write is exactly what you say, and vice versa. There is no silent letters, no irregular spelling, no homophone confusion. Every spoken Lojban sentence can be transcribed into written Lojban and back without any ambiguity.

This is why:

• The apostrophe (for /h/) must be written every time it's pronounced
• The period (pause) must be written before vowel-initial words
• Stress is regular and predictable — never needs marking

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Allophones and Variation#

Lojban phonology specifies phoneme targets but allows considerable phonetic variation:

• r can be any r-sound: trilled /r/, flapped /ɾ/, retroflex /ɻ/, approximant /ɹ/
• n before k/g can be /ŋ/ (as in English sing)
• Vowels may be somewhat lax in unstressed syllables
• l can be clear or dark

The key is that each sound must be distinguishable from all others. Lojban does not require "perfect" pronunciation — only distinct pronunciation.

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Summary#

• English-first learners: see If English is your first language — c/j/x/g/y, diphthongs as one syllable, . = pause

Chapter 20. selma'o Catalogue#

A selma'o is a grammatical word-class in Lojban — a group of cmavo that share the same grammatical behavior. Knowing a cmavo's selma'o tells you exactly where it can appear in a sentence. This chapter provides a reference catalogue of all major selma'o with their key members and functions.

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A — Sumti Logical Connectives (eks)#

Connects two sumti logically. Used between sumti in afterthought position.

mi .e do klama — I and you go.

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BAI — Modal Tags#

Pre-built modal/case tags. Attach to selbri as tense-like tags. See Chapter 10.

Key members: mu'i (motivated by), ki'u (justified by), ri'a (physical cause), ni'i (logical entailment), sepi'o (using tool), bai (compelled by), gau (agent), fi'o (custom modal — followed by any selbri).

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BE / BEI / BEhO — Inner Slot Fillers#

Used inside descriptions to fill numbered places of the selbri.

le dunda be le rozgu bei mi — the giver of the rose to me.

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BO — Closest Scope Grouper#

bo right-groups two adjacent elements (tanru components, sentences, sumti).

mi .e do bo mi'o klama — I, and (you-and-I), go. (grouping with bo)

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BY — Letter Names#

The selma'o containing all lerfu names: .abu .ebu .ibu .obu .ubu ybu by. cy. dy. … etc. See Chapter 18.

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CAhA — Actuality/Potentiality#

Marks whether a bridi is actual, potential, or a general law.

mi ka'e limna — I am capable of swimming (but maybe haven't). mi pu'i limna — I can swim and have done so.

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COI — Vocative Markers#

Used to address people or open communications.

coi .djan. doi .alis. — Hello John, [addressing] Alice.

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CUhE — Tense/Modal Question#

cu'e asks "what tense/modal applies?":

cu'e do klama — When/how are you going?

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DAhO — Assignment Canceller#

da'o cancels all current pronoun assignments (ko'a, ko'e, broda, etc.) without a topic change.

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DOI — Vocative Marker#

doi introduces a direct address (vocative). May optionally precede the name; also used alone to re-address.

doi .alis. klama — Alice, go!

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FA — Place Tags#

Tags for explicitly marking sumti places. Used when reordering arguments.

klama fa mi fe le zarci — go, x₁=I, x₂=the store.

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GA — Forethought Logical Connectives (geks)#

Forethought connectives that precede both sentences; gi separates them.

ge mi klama gi do cadzu — Both I go and you walk.

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GAhO — Interval Boundary Markers#

Modifies interval expressions to indicate open/closed boundaries:

mi cadzu ga'o le zarci ke'i le briju — I walk from the store (inclusive) to the office (exclusive).

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GIhA — Bridi-Tail Connectives (giheks)#

Connects two bridi-tails sharing the same x₁.

mi citka gi'e pinxe — I eat and drink.

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GOI — Relative Phrase Markers#

Introduces relative phrases (possessives and identifiers). See Chapter 11.

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GOhA — Pro-bridi#

Anaphoric references to previous bridi. See Chapter 5.

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GUhA — Forethought Selbri Connectives (guheks)#

Forethought connectives inside tanru/selbri:

gu'e blanu gi xunre gerku — a both-blue-and-red dog.

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I — Sentence Separator#

.i separates sentences. Can be compounded with connectives and modals:

.i — new sentence (same topic) .ije — and (next sentence) .ibo — closely related next sentence ni'o — new paragraph/topic (selma'o NIhO)

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JA — Tanru/Selbri Connectives (jeks)#

Logical connectives used within tanru or between selbri:

barda je blanu — big and blue.

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JOI — Non-Logical Connectives (joiks)#

Non-logical connectives for masses, sets, sequences, alternation:

mi joi do — me-and-you as a single mass. la .alis. ce la .djan. — the set {Alice, John}.

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KE / KEhE — Tanru Grouping#

ke opens a grouping in tanru; ke'e closes it (elidable at end of selbri). Also used for scalar negation scope: na'e ke … ke'e.

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KEI — Abstraction Terminator#

kei closes all NU abstractions. Elidable at end of bridi or before cu.

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KOhA — Pro-sumti#

The large class of sumti-replacing cmavo. See Chapter 5.

Subgroups:

• mi-series: mi, do, mi'o, ma'a, mi'a, do'o, ko
• ti-series: ti, ta, tu
• di'u-series: di'u, di'e, dei, do'i
• ko'a-series: ko'a–ko'u (assignable with goi)
• ri-series: ri, ra, ru (anaphoric)
• vo'a-series: vo'a–vo'e (reflexive)
• da-series: da, de, di (logical variables)
• Special: zo'e (unspecified), zu'i (typical), ce'u (lambda), ma (question), ke'a (relative clause)

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LE — Description Operators#

All the gadri (article-like words) that build sumti from selbri. See Chapter 3.

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NA — Bridi Negation#

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NAhE — Scalar Negation#

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NIhO — Paragraph Markers#

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NU — Abstractors#

All NU cmavo package a bridi as an abstraction sumti. See Chapter 12.

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PU — Tense (Temporal Direction)#

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SE — Place Conversion#

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UI — Attitudinals and Discursives#

The large class of free-modifier particles expressing emotion, attitude, evidential stance, and discourse structure. See Chapter 7.

Key members: .ui (happy), .oi (pain), .au (desire), .ai (intent), .ei (obligation), pe'i (I opine), ti'e (reportedly), ka'u (I know by experience), ru'a (I postulate), ju'a (I assert), pau (question marker), pei (attitude question), dai (empathy), fu'i (easy), bi'u (new information), si'a (similarly).

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VA — Spatial Distance#

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ZAhO — Aspect (Event Contour)#

See Chapter 16 for full table. Key members: pu'o (about to), co'a (starts), ca'o (ongoing), co'u (stops), mo'u (completes), za'o (too long), ba'o (resultant state), co'i (whole event).

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ZI — Temporal Distance#

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ZOI — Foreign Quote#

zoi introduces a foreign-text quotation using delimiter words. la'o does the same but creates a name sumti. See Chapter 17.

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ZOhU — Topic/Comment Separator#

zo'u separates the topic (or prenex) from the comment bridi. See Chapter 17.

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Alphabetical supplement — more selma'o (short index)#

The subsections above are grouped by topic. The table below lists additional common selma'o in alphabetical order with a one-line role and a pointer to where this book treats them (or to the chapter that uses them most). Use it when you meet a cmavo in the wild and want a quick label.

The alphabetical supplement above and the topic table earlier in this chapter cover all selmaʼo a learner will encounter. Rarer classes and specialist examples are addressed where their cmavo are introduced throughout this book.

Beyond this catalogue#

This chapter covers all selmaʼo a learner needs, organised by topic (earlier tables) and alphabetically (the supplement above).

-- cmavo lookup by class: jbovlaste lists every cmavo with rafsi and official gloss.

• Formal grammar: Chapter 21 of this book gives a prose overview of the formal rules; parser tools are linked there.

Chapter 21. Formal Grammar#

What Is the Formal Grammar?#

Lojban's grammar is defined by a formal EBNF (Extended Backus-Naur Form) grammar — a precise mathematical specification of every legal sentence. This is what makes Lojban genuinely unambiguous: there is exactly one parse tree for every grammatical Lojban expression.

This chapter summarizes the key structural rules in reader-friendly terms. It does not duplicate the full EBNF rules or selma’o cross-reference tables line-for-line.

Where the machine grammar lives#

The complete formal grammar of Lojban is specified as an EBNF (PEG) machine grammar. You do not need to read it to speak Lojban, but knowing it exists explains why "the parser says no" can have a definitive answer.

Key resources for the formal grammar:

• Parser tools: camxes, ilmentufa, and other community parsers accept a Lojban string and return its parse tree or an error — the fastest way to check a tricky sentence.
• cmavo by selmaʼo: Chapter 20 of this book catalogues every selmaʼo with examples; jbovlaste lists individual cmavo.
• Abbreviated EBNF for key rules — the table below gives the handful of non-terminals that most affect learners.

Using this friendly chapter: treat these sections as a conceptual map (templates, scope, elision). If a parser rejects a sentence, check the formal chapter and your parser’s documented baseline — community grammars evolve; the friendly text may simplify or reorder explanations for teaching.

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The Hierarchy of Lojban Structure#

Lojban utterances are built up through nested layers:

text
 └── paragraphs (ni'o / no'i groups)
      └── sentences (.i separated)
           └── _bridi_
                ├── prenex (... zo'u)
                ├── _sumti_ (arguments)
                └── _selbri_ (predicate)
                     ├── _brivla_ (single word)
                     ├── _tanru_ (_brivla_ sequence)
                     └── abstraction (NU + _bridi_ + kei)

Each level can contain connectives, tense tags, attitudinals, and terminators.

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The Core Bridi Template#

A canonical bridi has this structure:

[prenex zo'u] [_sumti_...] [tense] [NA] _selbri_ [_sumti_...] [vau]

More precisely:

[topic zo'u] [FA-tag] _sumti_ [cu] [tense/modal] [na] _selbri_ [_sumti_...] [vau]

cu separates the pre-selbri sumti from the selbri itself and is required when the sumti might otherwise be parsed as part of a tanru.

vau closes the bridi (almost always elidable, but terminates any implicit open bridi).

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Sumti#

A sumti is any of:

Sumti can be followed by relative clauses (poi/noi … ku'o), relative phrases (pe/po/ne + sumti), or be/bei/be'o inner-slot fillers when embedded in a description.

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Selbri#

A selbri is any of:

The co operator inverts the tanru so the post-co word is the modifier and the pre-co word is the head:

A co B  =  B-type A  (B modifies A)

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Tense Structure#

Tense is a prefix on the selbri (before na and the selbri itself):

[PU] [ZI] [FAhA] [VA] [ZAhO] [CAhA]  _selbri_

Each component is optional and they stack left-to-right, each adding a leg of the "imaginary journey":

• PU = temporal direction (pu/ca/ba)
• ZI = temporal distance (zi/za/zu)
• FAhA = spatial direction (zu'a, ri'u, etc.)
• VA = spatial distance (vi/va/vu)
• ZAhO = aspect (co'a, ca'o, co'u, etc.)
• CAhA = actuality/potentiality (ca'a, ka'e, etc.)

A tense may be followed by ki to set it as a persistent reference point for subsequent sentences.

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Logical Connective Forms#

Lojban has six positions where logical connectives appear, each with its own cmavo class:

All connectives follow the same four-vowel system (A/E/O/U) encoding the same truth functions regardless of position.

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Terminator Elision Rules#

Lojban has many optional terminators. The general rule: a terminator can be elided when the next word unambiguously signals the end of the current construction.

Key terminators and their elision conditions:

When elision is unsafe (keep the terminator):#

1. Ambiguity with following word:

le gerku poi blabi ku'o cu barda → safe to elide ku'o le gerku poi blabi cu barda = same meaning (cu ends the poi clause unambiguously)

But:

le gerku poi le nanmu pu viska — does this end after viska? Or does more follow? le gerku poi le nanmu pu viska ku'o cu batci — explicit ku'o needed here because cu is far away

2. be/bei before a relative clause:

le dunda be le rozgu poi melbi — ambiguous: does poi attach to le rozgu or to the whole dunda be le rozgu? le dunda be le rozgu be'o poi melbi — clear: poi attaches to the whole dunda-construction

3. Nested abstractions:

le du'u le nu mi klama kei cu vajni — kei needed to close the inner nu before the outer bridi continues

4. Stacking sumti without clear boundary:

mi djuno le du'u do klama le zarci — the LE stacks are closed by context mi djuno le du'u do klama le zarci ku kei — explicit if the outer bridi continues with more sumti

The elision hierarchy (informal rule of thumb):#

Terminators lower in this list are more commonly elided than those above them:

1. li'u — least often elided (keeps quotes clearly bounded)
2. be'o — elide only at end of description
3. ku'o — elide when cu or .i follows
4. kei — elide when cu follows
5. ku — usually safe to elide
6. vau — almost always safe

The parser is greedy: it absorbs as much as it can into the current construction. So ku, kei, and ku'o tell the parser "stop here" — without them, the parser keeps extending.

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Free Modifiers (Free Grammar)#

Many constructs can appear almost anywhere in a sentence without changing the parse. These have "free grammar" — they attach to whatever is nearest them:

• Attitudinals (UI): .ui, .oi, pe'i, ti'e, etc.
• Discursives (UI): ku'i (however), ta'o (incidentally), mi'u (ditto)
• to … toi: parenthetical remarks
• sei … se'u: metalinguistic commentary
• xi: subscript

Free modifiers do not change the syntactic parse; they only add pragmatic/attitudinal color.

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Prenex and Quantifier Logic#

zo'u and the Prenex#

zo'u is the grammatical separator between a prenex and the bridi body. Its grammar role is unambiguous: everything before zo'u is the prenex (a sequence of quantified sumti), everything after is the bridi.

ro da poi prenu zo'u da morsi
│ ← prenex ──────────│ ─ _bridi_ ──┤
"For all X that are persons: X dies."

The prenex binds logical variables (da, de, di, and their subscripted variants) with quantifiers. The variables then appear in the bridi body where they are used.

Why zo'u exists (grammar perspective)#

Without zo'u, a quantifier phrase like ro da poi prenu would be parsed as a sumti — just an argument filling a numbered place. There would be no structural way to indicate it binds the whole following bridi.

zo'u signals: "I am done listing the variables; everything that follows is the scope of those bindings." This is the Lojban equivalent of the mathematical ∀x ( … ) or ∃x ( … ) notation — zo'u is the opening parenthesis and the end of the bridi is the close.

Quantifier Types#

da zo'u da klama = ∃x: x goes = Something goes. ro da poi prenu zo'u da morsi = ∀x: person(x) → dies(x) = All persons die. su'o da poi gerku zo'u da blabi = ∃x: dog(x) ∧ white(x) = Some dog is white.

Scope Order#

The order of variables in the prenex determines scope. The leftmost variable has the widest scope (is the outermost quantifier):

ro da su'o de zo'u da dunda de mi = ∀x ∃y: x gives y to me = Everyone gives me something (possibly different things).

su'o de ro da zo'u da dunda de mi = ∃y ∀x: x gives y to me = There is one thing that everyone gives me (the same thing).

These have different meanings despite using the same words. Only the prenex order distinguishes them.

Inner Quantifiers vs. Prenex#

Quantifiers can also appear without a prenex, directly inside descriptions:

ro le prenu cu morsi = All the persons die. (inner quantifier on le) su'o lo gerku cu blabi = Some dog is white. (inner quantifier on lo)

These are equivalent to prenex quantifiers for most purposes, but the scope of inner quantifiers is limited to the bridi they appear in. They cannot extend across sentence boundaries.

Prenex variables (da, de, di) can extend across a whole discourse (until a da'o resets them). This is how Lojban expresses complex logical arguments:

da poi prenu zo'u da'e mlatu = There is a person such that [in all possible worlds] that person is a cat. (da ranges across the modal)

da'o: Resetting Variables#

da'o cancels all current pronoun and logical variable assignments, starting fresh. It is often placed after ni'o at major topic boundaries. Without da'o, a variable bound in one paragraph might unexpectedly still be bound in the next.

Useful Prenex Patterns#

Universal negation:

ro da poi prenu zo'u da na morsi = No person dies (literally: for all persons, they do not die).

Mutual relationship:

ro da ro de poi prenu zo'u ganai da prami de gi de prami da = For all persons A and B: if A loves B then B loves A. (mutual love claim)

Existential within universal:

ro da poi prenu zo'u su'o de poi plise zo'u da citka de = Every person eats some apple (they may eat different apples).

zo'u in topic-comment sentences: When zo'u appears with a non-variable sumti (like a description), it creates a topic-comment sentence rather than a logical prenex. The distinction is grammatical only in how the sentence is interpreted:

le finpe zo'u citka — The fish: [it/they] eat[s]. (topic-comment) da poi finpe zo'u da citka — For some fish: it eats. (logical prenex)

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The Grammar as a Whole#

Key properties of the formal Lojban grammar:

1. Unambiguous: every grammatical string has exactly one parse tree. No structural ambiguity.
2. Context-free (with some lexical lookups): the grammar can be parsed left-to-right with bounded lookahead.
3. Regular morphology: word-class (cmavo / brivla / cmene) is determinable from word shape alone, before parsing.
4. Audio-visual isomorphism: written form = spoken form with no exceptions.
5. Elidable terminators: formal grammar permits all terminators; spoken and written usage elides them when unambiguous.

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Quick Reference: Sentence Building#

A minimal grammatical Lojban bridi requires only a selbri:

klama — Someone/something goes to somewhere from somewhere.

Add x₁:

mi klama

Add x₂:

mi klama le zarci

Add tense:

mi pu klama le zarci

Add negation:

mi pu na klama le zarci

Add relative clause on sumti:

mi pu klama le zarci poi barda

Add modal:

mi pu klama le zarci mu'i le nu mi djica

Embed in abstraction:

le du'u mi pu klama le zarci cu vajni The proposition that I went to the store is important.

Each layer is added according to the formal grammar — and at each step the result is unambiguous.

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bu'a-series: Selbri Variables#

Just as da/de/di are bound variable sumti (standing for unknown things), bu'a/bu'e/bu'i are bound variable selbri — they stand for unknown predicates or relations:

da bu'a — Something stands in some relation. (existential claim about any relation)

ro da ro de zo'u ganai da bu'a de gi de bu'a da For all relations bu'a: if A bu'a B then B bu'a A. (claim that all such relations are symmetric)

bu'a/bu'e/bu'i work exactly like da/de/di — they are bound by quantifiers in the prenex and appear in the bridi body. They fill the selbri slot:

su'o bu'a zo'u mi bu'a do There is some relation that holds between me and you.

This is how Lojban makes claims about properties of properties — second-order logic. It's used in precise logical arguments and in formal definitions.

Prenex rule (CLL): You cannot write bare bu'a zo'u … — the prenex must contain sumti, and su'o bu'a (or ro bu'a, etc.) counts as an indefinite description in that slot, just like su'o nanmu. If you drop the prenex, you drop the explicit su'o too:

la .djim. bu'a la .djan. Jim stands in at least one relation to John. (implicit su'o)

If the quantifier on bu'a is anything other than su'o, keep the prenex:

ro bu'a zo'u la .djim. bu'a la .djan. For every relation F: Jim F John — usually false; needs ro bu'a in the prenex.

bu'a vs broda: Chapter 5 uses broda, brode, … as informal “slot-filler” brivla in examples. For bound predicate variables in a prenex, use bu'a/bu'e/bu'i (selma'o GOhA), not broda.

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A few more notes on variables#

Subscripts: If you need more than three sumti variables or three selbri variables, add a xi subscript — da xi vo, bu'a xi re — each (cmavo + subscript) pair is a fresh binding (Chapter 18 for xi notation).

Requantifying the same variable: Later in the bridi, ci da … re da … can pick out a subset of the things da already ranged over (e.g. three cats white, two of those cats big). Full detail is textbook logic; just remember later numbers are about the same da, not a new unrelated da.

Where this chapter sits: CLL’s logic chapter ends by noting that speakable predicate logic is open-ended — Lojban’s grammar is fixed, but the hardest metalogic is still research. Here you have the practical core: prenexes, naku movement, connectives, da and bu'a, and De Morgan. Deeper proof theory is the same as in any logic text, only with Lojban surface forms.

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De Morgan's Laws in Lojban#

De Morgan's laws state that logical negation distributes over connectives, swapping AND↔OR:

not(A and B) = (not A) or (not B) not(A or B) = (not A) and (not B)

In Lojban, these translate directly:

For sumti connectives:

naku la .alis. .e la .djan. cu klama = la .alis. na klama .a la .djan. na klama Not both Alice and John go = Alice doesn't go or John doesn't go.

For bridi connectives:

na ku ge la .alis. cu klama gi la .djan. cu klama = la .alis. na klama .a la .djan. na klama It's not the case that both go = One of them doesn't go.

The rule in connective vocabulary:

• Negating E (and) → A (or) with negated components: naE = nand
• Negating A (or) → E (and) with negated components: naA = nor

This is why the vowel+na+nai system covers all 16 truth functions — De Morgan lets you express every combination.

Quantifier De Morgan (covered in Chapter 13):

• naku ro da = su'o da naku — not-all = some-not
• naku su'o da = ro da naku — none = all-not

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naku Outside a Prenex: Full Treatment#

naku in a prenex position negates the scope of what follows with full quantifier interaction. Outside a prenex, it works as a "wide-scope na":

naku la .alis. cu klama

This is equivalent to la .alis. na klama for simple bridi but differs with quantifiers:

naku ro le prenu cu morsi Not every person dies. (= some person doesn't die — naku + ro = su'o na)

naku su'o le prenu cu morsi No person dies. (= every person doesn't die — naku + su'o = ro na)

The full table:

naku is most important in logical arguments and in understanding the precise scope of negation. For ordinary speech, na before the selbri is usually sufficient.

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Logic and Quantifiers#

Existential Claims: da, de, di#

The cmavo da, de, and di (selma'o KOhA) are logical variables — they stand for unknown things, like X, Y, and Z in logic notation.

The most basic use is an existential claim: asserting that something exists.

da viska mi There is an X such that X sees me. → Something sees me.

This does not presuppose that the listener knows what is doing the seeing — it only claims that something does.

A prenex makes the structure explicit. It consists of any number of variable declarations followed by zo'u:

da zo'u da viska mi There-is-an-X such-that: X sees me.

The prenex can hold multiple variables:

da de zo'u da prami de There-is-an-X, there-is-a-Y: X loves Y. → Somebody loves somebody.

Note: da and de can refer to the same thing unless that is explicitly ruled out. The sentence above does not mean "somebody loves somebody else."

da zo'u da prami da Somebody loves themselves.

Universal Claims: ro da#

When ro (all/every) precedes a variable, it makes a universal claim:

ro da zo'u da viska mi For every X: X sees me. → Everything sees me.

Mixed universal and existential claims have crucially different meanings depending on order:

ro da de zo'u da viska de For every X, there is a Y: X sees Y. → Everything sees something. (each thing sees something, possibly different somethings)

da ro de zo'u da viska de There is an X such that for every Y: X sees Y. → Something sees everything. (one particular thing sees all)

These mean completely different things. The order of variables in the prenex determines scope: the leftmost has the widest scope.

Restricted Variables: da poi#

Variables can be restricted to a subset using a poi relative clause:

da poi gerku cu vasxu There is an X which is a dog: X breathes. → Some dog breathes.

ro da poi gerku cu vasxu For every X which is a dog: X breathes. → Every dog breathes.

This is far more useful than unrestricted universal claims, which are almost never true about absolutely everything.

Dropping the Prenex#

The prenex is optional when the variables appear in the same order in the main bridi as they did in the prenex. In that case, just move any ro and poi to the first occurrence of the variable:

da viska mi — Something sees me. ro da poi gerku cu vasxu — Every dog breathes.

When variables need to appear in a different order than their scope order, you need the prenex explicitly. For example, to say "every person is bitten by some dog":

ro da poi prenu ku'o de poi gerku zo'u de batci da

Dropping the prenex here and reversing the order would instead say "some dog bites every person" — a completely different claim.

Generalized Quantifiers#

Any number can quantify a variable, not just ro (all) and su'o (at least one):

re da viska mi — Exactly two things see me. su'ore da viska mi — At least two things see me. no da viska mi — Nothing sees me. (zero things see me)

Note: bare da without an explicit quantifier implies su'o da (at least one). So da viska mi means "at least one thing sees me."

The distinction between exact and minimum counts:

• re = exactly two
• su'ore = at least two (su'o = "at least", re = "two")

Quantifier Scope and Grouping#

When two quantified expressions appear in the same bridi without a prenex, the left-to-right order determines scope:

ci gerku cu batci re nanmu Three dogs bite two men.

Does each dog bite the same two men, or possibly different pairs? In Lojban, the left variable (ci gerku) has wider scope — so there are three dogs each biting two men, possibly different ones. Up to six different men could be involved.

To make both quantifiers have equal scope (the same two men bitten by all three dogs), use a termset with ce'e:

ci gerku ce'e re nanmu cu batci Three dogs [together with] two men bite. (the same two men are bitten by all three dogs)

The Problem of "Any"#

English "any" is ambiguous. Lojban treats the two senses differently:

Universal "any" (anyone who does X also does Y): use ro da poi:

ro da poi klama le zarci cu cadzu le foldi Everyone who goes to the store walks across the field.

This asserts that there are people going to the store (universal claims imply the existential). If you want a purely conditional statement with no such implication, use the logical connective go (if-and-only-if):

ro da zo'u da go klama le zarci gi cadzu le foldi For every X: X goes to the store if and only if X walks across the field.

This does not imply that anyone actually goes to the store.

Existential "any" (I need any box = I need a box, one will do): when the existence is inside a want/need/possibility context, bind the variable in the inner prenex:

mi nitcu lo nu da poi tanxe gi'e bramau ti zo'u mi ponse da I need an event of: there existing a box bigger than this that I own.

The da is existential only within the nu abstraction — it doesn't assert the box exists in the real world right now, only in the needed event.

Negation Boundaries#

When naku appears in a prenex, it creates a negation boundary. Moving naku past a quantifier inverts it: ro ↔ su'o.

Starting from:

ro da su'o de zo'u da prami de Everybody loves at least one thing.

Negate it:

naku ro da su'o de zo'u da prami de It is false that everybody loves at least one thing.

Moving naku rightward past ro da (inverting ro → su'o):

su'o da naku su'o de zo'u da prami de There is someone who doesn't love anything.

Moving it one more step past su'o de (inverting su'o → ro):

su'o da ro de naku zo'u da prami de There is someone who, for each thing, doesn't love that thing.

All three forms are logically equivalent. The rule: every time naku crosses a quantifier boundary, invert the quantifier (ro↔su'o). Double negatives in adjacent position cancel.

The quantifier no (zero) is shorthand for naku su'o — none means not-at-least-one. To negate a noda sentence, first expand it:

noda vasxu = naku su'o da vasxu → negation = su'o da vasxu (something breathes)

Terminator Elision: Context Rules#

The Lojban parser is greedy — it consumes as much as possible into the current construction before stopping. Terminators tell the parser where to stop. Knowing when elision is safe requires understanding what the parser would do without the terminator:

Always safe to elide (parser cannot be misled):

• vau at the end of a sentence before .i or end of text
• li'u at the very end of a bridi (nothing follows in the same sentence)
• do'u after a vocative phrase at sentence start
• kei at the end of the entire sentence
• ku after a description that immediately precedes the selbri via cu

Usually safe to elide (by convention, rarely ambiguous):

• ku before most selbri
• ge'u (GOI terminator) before sentence-final position
• be'o when the be/bei chain is the final component of a tanru

Must keep (parser will extend the construction otherwise):

Heuristic: elide terminators by default; restore them one at a time if a canonical Lojban parser (e.g., camxes) rejects or misparses the sentence.

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PA Role Ambiguity#

A PA (number) cmavo can fill several roles in the same grammatical position, creating ambiguity that requires context or terminators to resolve:

Role 1 — Outer quantifier (before a description):

re le gerku cu blabi Two of the dogs are white. (re = outer quantifier)

Role 2 — Inner quantifier (between descriptor and selbri):

le re gerku cu blabi The two dogs are white. (re = inner quantifier of le)

Role 3 — Bare number sumti (standalone):

re cu klama Two (things) come. (re = number standing alone as sumti, implies lo re)

Role 4 — Part of a mekso expression:

li re su'i ci du li mu 2 + 3 = 5 (re = numeral inside li…)

Role 5 — MOI selbri (with a MOI cmavo):

mi pamoi I am first. (pa + moi → ordinal selbri)

Role 6 — Part of a quantifier phrase (with ROI/MAI/etc.):

mi reroi tavla I talk twice. (re + roi = twice)

The critical ambiguity — a number immediately before a selbri could be outer quantifier or mekso:

pa klama = one comes (outer quantifier — someone comes) li pa = the number 1 (inside li... unambiguous)

When a number precedes a le/lo description directly, it is unambiguously an outer quantifier. When a number appears with no descriptor before a selbri, it is read as outer quantifier over an implicit lo. To use a number as a mekso value outside li…, wrap it in li.

PA before selbri after ku — the specific trap:

le gerku ku pa blabi

Without ku this is: le gerku pa blabi — the parser could read pa as the inner quantifier of le gerku or the outer quantifier before blabi. The ku terminates the description cleanly, making pa unambiguously the outer quantifier for blabi.

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Summary#

The formal Lojban grammar defines:

• Three word classes (cmavo, brivla, cmene) by morphological shape
• Bridi structure: prenex + sumti + tense + selbri + sumti
• Tense as a stacked prefix (PU ZI FAhA VA ZAhO CAhA)
• Six connective positions with consistent truth-function vocabulary
• Terminator elision rules (greedy parser; elide when unambiguous; keep be'o before poi/noi, kei before nested sumti)
• Free modifier attachment (attitudinals, discursives, to/toi, sei/se'u)
• Quantifier prenex for logical variables

Terminator elision key points:

• The parser is greedy — terminators tell it where to stop
• li'u almost always kept; vau almost always dropped
• be'o required before relative clauses; kei required in nested abstractions
• When in doubt, include terminators

Prenex / quantifier scope key points:

• zo'u grammatically separates prenex from bridi body
• Leftmost prenex variable has widest scope (outermost quantifier)
• ro da su'o de zo'u ≠ su'o de ro da zo'u — order controls meaning
• Inner quantifiers (ro le) are scoped to one bridi; prenex variables (da) can span discourse
• da'o resets all variable bindings

Selbri variables:

• bu'a/bu'e/bu'i = bound variable selbri (stand for unknown predicates)
• su'o bu'a zo'u required in prenex (not bare bu'a zo'u); drop prenex ⇒ drop explicit su'o
• ro bu'a etc. keep the prenex; broda is informal — use bu'a for real variable binding
• xi subscripts extend da/… and bu'a/… when three of each are not enough

De Morgan's laws:

• naku (A and B) = (not A) or (not B)
• naku (A or B) = (not A) and (not B)
• naku ro da = su'o da naku (not-all = some-not)
• naku su'o da = ro da naku (none = all-not)

Logical variables and quantifiers:

• da/de/di = existential variables (something, something-else, a-third-thing)
• Bare da implies su'o da (at least one); explicit ro da = for all
• Prenex: da de zo'u … — leftmost variable has widest scope
• Dropping the prenex: legal when variable scope order matches bridi order
• da poi [bridi] = restricted variable: only X that satisfy [bridi]

Quantifier scope:

• Left-to-right order in a bridi determines scope: ci gerku cu batci re nanmu → 3 dogs each bite 2 (possibly different) men
• Use a termset (ce'e) to force equal scope: both quantifiers range over the same objects

The problem of "any":

• Universal "any" (every X that…) → ro da poi …
• ro da poi implies the set is non-empty; for pure conditionality use go in a prenex
• Existential "any" (one will do) → bind da inside an inner abstraction (nu, ka, etc.) so it is existential only within that scope

Negation boundaries:

• naku in a prenex creates a scope boundary; moving it past a quantifier inverts it: ro ↔ su'o
• no da = naku su'o da (none = not-at-least-one); negate it → su'o da
• Each time naku crosses one quantifier boundary, that quantifier flips; two adjacent negatives cancel

Formal spec: This friendly chapter is the conceptual skeleton — enough to see why sentences parse as they do. For machine-readable rules, use one of the parser tools listed in Where the machine grammar lives above.