Chapter 5. Times, days, dates (and abstractions)

Table of Contents
What is the time?
Times and Events
Times and Events, Improved: Conversion
Times and Events, Improved #2: sumti tcita
Days and Months
Answers to Exercises

What is the time?

One way to ask the question "What is the time?" is ma tcika ti. We know that ma is the sumti question word ('what'), so tcika must be a selbri meaning 'is the time'. The place structure of tcika is

x1 (hours, minutes, seconds) is the time of state/event x2 on day/date x3, at location x4, by calendar x5

So in Lojban, times do not exist in the abstract: times are always the times of something. So we ask what the time is of ti, meaning 'this event/thing', or, in other words 'now'.

Note: Well, we don't really; stay tuned for next lesson, where we'll fill this in a little more.

A full answer would obviously be very long-winded, but remembering the Lojban convention that you miss out all the places after the last one you really need, a typical exchange would be:

  • ma tcika ti

  • li papa

  • What's the time?

  • Eleven

Note the li, since we are talking about a number here. li papa is short for li papa cu tcika ti — "the number eleven is the time of this (event)".

If we want to be a bit more precise, we need to use pi'e. This introduces fractional parts of numbers like pi, but unlike pi it doesn't need to indicate decimal fractions in a number. In fact, the kind of fractional part it does indicate can vary within the same number. In normal counting, pi is a decimal point, in hexadecimal it's a hexadecimal point and so on, but the kind of fraction it indicates never changes its value. But pi'e doesn't have that restriction; so we can use it to separate hours from minutes (which are sixtieths of hours), or, as we will see below, days from hours (which are twenty-fourths of days). pi'e, in other words, means 'part', not 'decimal point'. So an alternative answer to the question could be

li papa pi'e mu
11:05 (Five past eleven)
(The number eleven, and five parts)

or if you want to be particularly precise,

li papa pi'e mu pi'e pabi
Five minutes and eighteen seconds past eleven
(The number eleven, and five parts, and eighteen parts of parts)

Let's imagine, though, that the time is not five past eleven, but five to eleven. We can say li pano pi'e mumu (10:55), but we can also say li papa pi'e ni'u mu, where ni'u is the Lojban minus sign (for negative numbers, not for subtraction) — what we are saying is '11:−5'.

For 'half past eleven' you can also use pi and say li papa pimu '11.5'. I don't particularly like this method, but it is perfectly good Lojban. If we are using numbers for times, it is normal to use the 24-hour system, so 6 PM is li pabi (18:00).

If you want to use twelve-hour time instead, you need some way of distinguishing between AM and PM. The conventional way in Lojban is to use cmene for hours (so we can add supplementary information like that later on, as part of the cmene.) So 'four o'clock' is la vocac., 'five o'clock' is la mucac. and so on (from cacra 'hour'). For 11 and 12 we need extra numbers. Fortunately Lojban has these and more; the number system actually goes up to 16 (hexadecimal), so we have the extra numbers













Obviously for anything other than talking about computer programming, the numbers 13–15 are useless, but we can use 10–12 for hours. 'Ten o'clock' under this scheme is la daucac., 'eleven o'clock' is la feicac., and 'twelve o'clock' is la gaicac. . For 'morning' and 'evening' we can then add lir. and lec., meaning 'early' and 'late' (from clira and lerci). So la mucac. lir. is five in the morning.

As you can see, things start to get a little messy with the 12-hour system (how do you say 9:22 AM?), so the 24-hour system is preferred by popular acclamation.

Exercise 1

What are the following times in Lojban?

  1. Nine o'clock

  2. Eleven o'clock in the morning

  3. Two in the afternoon

  4. A quarter to twelve

  5. Midnight

  6. 9:25

  7. 12:15

  8. 14:30

  9. 17:03

  10. 20:00:03

  11. 21:54:16.71