Restrictive and non-restrictive

We've learnt how to use relative clauses to narrow things down. But not all relative clauses are used for that purpose. Sometimes they are used just to supply extra information about someone or something whose identity we've already worked out. For example, if I say

Lojban, which is descended from (Institute) Loglan, has a public domain grammar

I'm hardly saying that Lojban is descended from Institute Loglan, in order to distinguish it from the scores of Lojbans not descended from Loglan! Instead, I'm providing extra, incidental information, to fill in the listener or reader.

This means that there are two kinds of relative clause: restrictive, like we've been discussing until now, and non-restrictive, like what we've just seen. The grammar of these kinds of relative clause is different in many languages. In American English, for example, style guides recommend that you keep who and which for non-restrictives, and use that for restrictives. ("The Lojban that I learned in 1993 is somewhat different from contemporary Lojban.") Furthermore, non-restrictive relative clauses in English usually have a comma in front of them, in writing, and a little pause in front of them, in speaking: this kind of clause is pretty much a parenthetical remark, and is marked out like one.

Lojban distinguishes between the two kinds of relative clause by the word that introduces them: non-restrictive relative clauses start with noi, rather than poi. Otherwise, their grammar is identical:

la lojban. noi [ke'a] se dzena la loglan. pe le ckule cu se gerna lo gubni
Lojban, which (non-restrictive) [it] has-the-ancestor Loglan-of-the-institute, has-as-its-grammar something-public

(Yes, that's the old "cu closing off everything in its wake" trick in action.)

Note: The restrictive/non-restrictive divide also applies to a word we saw back in Lesson 3: pe. This word is in fact a special case of a relative clause (introducing a sumti rather than a complete bridi.) Since it is a relative clause in a way, it too can have a non-restrictive version: ne.

Exercise 5

Are the relative clauses in the following English sentences restrictive or non-restrictive? We've left off any punctuation hints like commas or choice of correct relativisers, so some sentences will sound a little odd.

  1. This is the way that the world ends.

  2. I saw the same waiter that I saw last night.

  3. This is my friend Zhang that I already told you about.

  4. Then came a full train that I wasn't going to bother boarding.

  5. I'm doing the best that I can.

  6. Radiophones that are generally known as radios are prevalent at the majority of work places.

  7. I don't like what has happened.

  8. I live in the city centre where the rent is more expensive.