The following cmavo are discussed in this section:
ti KOhA ti-series this here, a nearby object
ta KOhA ti-series that there, a medium-distant object
tu KOhA ti-series that yonder, a far-distant object
It is often useful to refer to things by pointing to them or by some related non-linguistic mechanism. In English, the words “this” and “that” serve this function among others: “this” refers to something pointed at that is near the speaker, and “that” refers to something further away. The Lojban pro-sumti of the ti-series serve the same functions, but more narrowly. The cmavo “ti”, “ta”, and “tu” provide only the pointing function of “this” and “that”; they are not used to refer to things that cannot be pointed at.
There are three pro-sumti of the ti-series rather than just two because it is often useful to distinguish between objects that are at more than two different distances. Japanese, among other languages, regularly does this. Until the 16th century, English did too; the pronoun “that” referred to something at a medium distance from the speaker, and the now-archaic pronoun “yon” to something far away.
In conversation, there is a special rule about “ta” and “tu” that is often helpful in interpreting them. When used contrastingly, “ta” refers to something that is near the listener, whereas “tu” refers to something far from both speaker and listener. This makes for a parallelism between “ti” and “mi”, and “ta” and “do”, that is convenient when pointing is not possible; for example, when talking by telephone. In written text, on the other hand, the meaning of the ti-series is inherently vague; is the writer to be taken as pointing to something, and if so, to what? In all cases, what counts as “near” and “far away” is relative to the current situation.
It is important to distinguish between the English pronoun “this” and the English adjective “this” as in “this boat”. The latter is not represented in Lojban by “ti”:
3.1) le ti bloti
the this boat
does not mean “this boat” but rather “this one’s boat”, “the boat associated with this thing”, as explained in Chapter 8. A correct Lojban translation of Example 3.1 is
3.2) le vi bloti
the here boat
the nearby boat
using a spatial tense before the selbri “bloti” to express that the boat is near the speaker. (Tenses are explained in full in Chapter 11.) Another correct translation would be:
3.3) ti noi bloti
this-thing which-incidentally is-a-boat
There are no demonstrative pro-bridi to correspond to the ti-series: you can’t point to a relationship.