Chapter 10: Imaginary Journeys: The Lojban Space/Time Tense System

8. Movement in space: MOhI

The following cmavo is discussed in this section:

mo'i    MOhI    movement flag

All the information carried by the tense constructs so far presented has been presumed to be static: the bridi is occurring somewhere or other in space and time, more or less remote from the speaker. Suppose the truth of the bridi itself depends on the result of a movement, or represents an action being done while the speaker is moving? This too can be represented by the tense system, using the cmavo “mo'i” (of selma'o MOhI) plus a spatial direction and optional distance; the direction now refers to a direction of motion rather than a static direction from the speaker.

✥8.1  le verba mo'i ri'u cadzu le bisli
The child [movement] [right] walks-on the ice.
The child walks toward my right on the ice.

This is quite different from:

✥8.2  le verba ri'u cadzu le bisli
The child [right] walks-on the ice.
To the right of me, the child walks on the ice.

In either case, however, the reference frame for defining “right” and “left” is the speaker's, not the child's. This can be changed thus:

✥8.3  le verba mo'i ri'u cadzu le bisli
    ma'i vo'a
The child [movement] [right] walks on the ice
    in-reference-frame the-x1-place.
The child walks toward her right on the ice.

✥8.3 is analogous to ✥8.1. The cmavo “ma'i” belongs to selma'o BAI (explained in Chapter 9), and allows specifying a reference frame.

Both a regular and a “mo'i”-flagged spatial tense can be combined, with the “mo'i” construct coming last:

✥8.4  le verba zu'avu mo'i ri'uvi
    cadzu le bisli
The child [left] [long] [movement] [right] [short]
    walks-on the ice.
Far to the left of me, the child walks a short
    distance toward my right on the ice.

It is not grammatical to use multiple directions like “zu'a ca'u” after “mo'i”, but complex movements can be expressed in a separate bridi.

Here is an example of a movement tense on a bridi not inherently involving movement:

✥8.5  mi mo'i ca'uvu citka le mi sanmi
I [movement] [front] [long] eat my meal.
While moving a long way forward, I eat my meal.

(Perhaps I am eating in an airplane.)

There is no parallel facility in Lojban at present for expressing movement in time — time travel — but one could be added easily if it ever becomes useful.