Chapter 2: A Quick Tour of Lojban Grammar, With Diagrams

17. Tenses

In English, every verb is tagged for the grammatical category called tense: past, present, or future. The sentence

✥17.1    John went to the store

necessarily happens at some time in the past, whereas

✥17.2    John is going to the store

is necessarily happening right now.

The Lojban sentence

✥17.3    la djan.  [cu] klama         le
zarci
  --------  ==========         --------
  John      goes/went/will   go to-the store

serves as a translation of either ✥17.1 or ✥17.2 , and of many other possible English sentences as well. it is not marked for tense, and can refer to an event in the past, the present or the future. This rule does not mean that Lojban has no way of representing the time of an event. A close translation of ✥17.1 would be:

✥17.4    la djan.   pu klama    le zarci
  --------   ========    --------
  John       [past] goes to-the store

where the tag “pu” forces the sentence to refer to a time in the past. Similarly,

✥17.5    la djan.   ca klama       le
zarci
  --------   ========       --------
  John       [present] goes to-the store

necessarily refers to the present, because of the tag “ca”. Tags used in this way always appear at the very beginning of the selbri, just after the “cu”, and they may make a “cu” unnecessary, since tags cannot be absorbed into tanru. Note that ✥17.3 has and requires a “cu” to prevent “bajra” and “klama” from forming a tanru, but ✥17.4 and ✥17.5 lack the unnecessary “cu”. Such tags serve as an equivalent to English tenses and adverbs. In Lojban, tense information is completely optional. If unspecified, the appropriate tense is picked up from context.

Lojban also extends the notion of “tense” to refer not only to time but to space. The following example uses the tag “vu” to specify that the event it describes happens far away from the speaker:

✥17.6    do [cu] vu vecnu    zo'e
  --      ========
  You     yonder sell something-unspecified.

In addition, tense tags (either for time or space) can be prefixed to the selbri of a description, producing a tensed sumti:

✥17.7    le pu bajra [ku] cu           
tavla
  ----------------               =====
  The earlier/former/past runner talked/talks.

(Since Lojban tense is optional, we don't know when he or she talks.)

Tensed sumti with space tags correspond roughly to the English use of “this” or “that” as adjectives, as in the following example, which uses the tag “vi” meaning “nearby”:

✥17.8    le vi bajra [ku]   cu tavla
  ----------------      =====
  The nearby runner     talks.
  This runner talks.

Do not confuse the use of “vi” in ✥17.8 with the cmavo “ti”, which also means “this”, but in the sense of “this thing”.

Furthermore, a tense tag can appear both on the selbri and within a description, as in the following example (where “ba” is the tag for future time):

✥17.9    le vi tavla [ku] cu ba klama
  ----------------    ========
  The here talker     [future] goes.
  The talker who is here will go
  This talker will go.