First Steps in Lojban
Lesson 6. Compounds (tanru)
Crêpes are amazing! And wow, I still can't believe how many cats there were!
Yeah... (There goes my diet...)
I'm all powered up now. Basic sentences are starting to feel like second nature!
Great. Once you're comfortable with simple sentences (bridi), we can start fleshing out the words themselves for more detailed expression. First, let's look at how to expand our selbri.
Chaining brivla builds tanru
In Lojban, you can chain multiple brivla (predicate words) together. This kind of chain is called a tanru.
blanu kanla mlatu blue-eyed cat
- blanu
- x1 is blue
- kanla
- x1 is an eye of x2
- mlatu
- x1 is a cat …
So the words on the left modify the ones on the right?
Precisely. And here's the cool part: tanru grouping is always unambiguous. Lojban has strict rules for how these chains are interpreted.
So there's no "attachment ambiguity"?
Exactly. The rules are very logical. Of course, the downside is that sometimes the grammar might force a grouping you didn't intend—so you have to pay attention.
The basic rule is simple: each word (or group of words) on the left modifies the immediate word to its right.
((blanu kanla) mlatu) ((blue eye) cat) — a "blue-eye" type of cat
((((stedu xunre) finpe) citka) mlatu) ((((red-head) fish) eating) cat) — a cat that eats red-headed fish
- stedu
- x1 is a head of x2
- xunre
- x1 is red
- finpe
- x1 is a fish …
- citka
- x1 eats x2
In natural languages, a phrase like "red-headed fish-eating cat" can be interpreted in several ways. But Lojban forces a single, specific structure.
That's what we mean by Lojban's syntactic precision. Tanru are a perfect example of that.
Lojban doesn't mess around, does it?
Tanru meanings are flexible
While the structure is precise, the meaning of a tanru is actually quite flexible. It usually just means "a Y that has something to do with X" or "an X-ish Y."
blanu mlatu blue cat — this could mean blue fur, blue eyes, or even a cat wearing a blue collar. Context decides the specifics.
Humans fill in the usual reading.
In ordinary situations, trust your intuition.
A tanru is still a selbri
A tanru functions as a single selbri. Its place structure is determined by the rightmost word (the "anchor" or "head" of the chain).
So, both blanu mlatu and stedu xunre finpe citka mlatu share the same place structure as the basic word mlatu.
ti blanu mlatu this is some kind of blue cat.
tu stedu xunre finpe citka mlatu that is a red-headed fish-eating cat (species unspecified).
True or false
Pick whether each statement is true or false according to the lesson.
You can form tanru by stringing selbri together.
Any tanru always has exactly one syntactic parse.
Any tanru always has exactly one meaning.
In blanu kanla mlatu, the grouping is ((blanu kanla) mlatu).
blanu mlatu can mean “a cat that lives in a blue house”.