Chapter 6. Time and Space — basic Lojban 'tenses'

Table of Contents
Time with sumti
Time and selbri
More negativity
Answers to exercises


Before we go on any further, we've left a little unfinished business from the previous lesson. This opens up a whole new set of issues, which is why we've held it over for this lesson.

Remember that when we speak of dates in Lojban, we also need to specify the place on the globe where the date was calculated. The instant Neil Armstrong made that small step for (a) man, for instance, it wasn't the 21st of July everywhere on Earth. In Tokyo, it was closer to the 22nd. So if we want to point out that it was the 21st, Houston time, we need to specify the x3 place of detri. That means we can simply say:

li repa pi'e ze pi'e pasoxaso cu detri lenu lo remna cu klama le lunra la xustyn.


Actually, no. Look at that sentence again. How would we say that the 21st was the day Armstrong went to the moon [going] from Houston? You guessed it —

li repa pi'e ze pi'e pasoxaso cu detri lenu lo remna cu klama le lunra la xustyn.

So now (Houston), we have a problem. Which selbri does la xustyn. belong to in this sentence? klama, or detri?

This kind of ambiguity is nothing new to natural languages, which tend to resolve problems like these with tricks like well-positioned pauses in speech, and punctuation in writing. (Consider for instance the English sentence 21/7/69 was the date a man went to the moon, from Houston. With that comma, you can only read that as "according to Houston.")

The trick Lojban uses instead, however, turns out to be one of its major 'selling points'. Lojban uses words called terminators. No, they aren't killer androids with difficult-to-spell surnames, but little words used to indicate when groups of words, such as phrases, end. You can think of them like the brackets used in mathematics, and they serve pretty much the same purpose. So in Lojban, whenever a structure begins whose length is not known in advance, a terminator goes at the end of the structure. This is what makes Lojban syntactically unambiguous:

This means that our sentence about the moon landing is fully elaborated like this (putting in some braces to make things clearer, and sneaking in the terminator lo'o corresponding to li):

[{li [repa pi'e ze pi'e pasoxaso boi] lo'o} cu detri [le{nu [{lo remna ku} cu klama {le lunra ku} vau] kei} ku] la xustyn. vau]

The kei goes before la xustyn. . This means that as a sumti, la xustyn. cannot belong to klama: kei has cordoned off the places of klama from the rest of the sentence (and the places of detri.) So la xustyn. can only be a sumti of the main selbri, detri.

The reader may well be wondering at this point how come they've never seen one of these terminators before. The reason is that Lojban is still meant to be spoken by humans, and keeping track of every single structure used in a sentence is more work than is reasonable to expect of any human. So when the sequence of words has an unambiguous structure, the terminators can be dropped out.

For example, if we see cu in a sentence, we know that what is coming up is a selbri; so the sumti before it must now be over. So we can drop the ku. (In fact, that's why cu exists in the first place: the beginning of a verb is a much more important structural break in natural languages than the end of a noun.) If a new sentence is beginning — as signalled by perhaps the most distinctively Lojbanic word, the 'audible punctuation' .i — then there can be no more sumti from the old sentence; so we drop the vau. In fact, it is only in situations of potential ambiguity, like the sentence we've been looking at, that you'll get terminators appearing in normal Lojban usage at all. So our two possible interpretations of the sentence with Neil Armstrong would normally appear as:

li repa pi'e ze pi'e pasoxaso cu detri {lenu lo remna cu klama le lunra la xustyn.} (date for going to the moon from Houston)

li repa pi'e ze pi'e pasoxaso cu detri {lenu lo remna cu klama le lunra kei} la xustyn. (date for going to the moon according to Houston)

Note: Remember those pesky possessive constructions from Lesson 3, when you couldn't flip le tamne pe le ninmu klama the other way around, because it was ambiguous? All you need is ku to resolve that ambiguity: le le ninmu klama ku tamne means 'the woman traveller's cousin', and le le ninmu ku klama tamne means 'the woman's traveller cousin.'

Still, most Lojbanists think the flip-around is not worth the hassle of inserting that bothersome ku, so you rarely see it used when the 'possessor' sumti is not a one-word sumti.



x1 walks/strides/paces on surface x2 using limbs x3


x1 tells about/describes x2 (object/event/state) to audience x3 with description x4 (property)


x1 dwells/lives/resides/abides at/inhabits/is a resident of location/habitat/nest/home/abode x2


x1 sits [assumes sitting position] on surface x2

Exercise 1

What do the following Lojban sentences mean when the highlighted terminators are present, and what do they mean when they are absent?

  1. mi skicu li re boi re lo pendo

  2. li pa pi'e cino tcika lenu mi prami kei la mumdjed.

  3. le nanmu cu zgana le mlatu vau

  4. le mamta pe le cifnu ku litru

  5. mi cpedu lenu la mari,as. tavla kei la klaudias.