## 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
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.