Part 3: Slot 1: tense and aspect

The first two ranks of the verb's dress: when (tense) and what shape in time (aspect). Two tense particles (to past, so future, present unmarked) and five aspects, each now with a ruled, non-overlapping territory.

The five aspects, carved

Canon carves the one blurred border: si is mid-flow only, ro is habit only, and they do not overlap. Every si in validated text is something unfolding under the speaker's eyes, and the language's most beloved habitual sits where it belongs, on ro, starting with the primer's first cat:

shia to si ke thalo.
3SG PST IPFV INFER walk.
(They were walking — as I read the signs.)

misheko ro nulae.
cat HAB sleep.
(The cat always sleeps.)

The judgment call is one question: am I inside one occasion, or standing back from many? Inside, si. Standing back, ro. And te carries a design note worth savoring: Phi has no verb stop: cessation is the particle, so nothing ever "stops" except as the gentle ending of some named, ongoing thing (canon, covered by design).

ki and the reference time

ki's ruling makes the perfective fully compositional: tense sets a reference time, and ki says complete as of it.

thia ki shonela.
2SG PFV learn.
(You have learned.)

mia to ki nila.
1SG PST PFV see.
(I had seen.)

mia so ki nila.
1SG FUT PFV see.
(I will have seen.)

One aspect, three English tenses, zero new machinery: the tense particle does all the moving. This is the stack teaching its own lesson: particles compose; they never blend.

Tense times aspect

Every tense-aspect pair is meaningful, and the meanings are exactly what composition predicts: to si was doing, so si will be doing, to ro used to (the habit held, then), so ro will habitually (the habit is coming), to pa began, te alone stops now. Ten cells, no idioms, no exceptions: the grid in Part 8 lays them all out.

Drill: say the time-shape

Translate aloud, choosing tense and aspect and nothing else, with subject lopia and verb wile (play):

1. The child is playing (right now, mid-game).
2. The child plays (habitually: that is what recess is).
3. The child began to play.
4. The child had played (before the meal, complete).
5. The child will have played.
6. The child stopped playing.

Answers: 1 lopia si wile. 2 lopia ro wile. 3 lopia to pa wile. 4 lopia to ki wile. 5 lopia so ki wile. 6 lopia to te wile. And if you wrote si for 2 or ro for 1, run the carve question again: inside one occasion, or standing back from many? The border is one question wide, and it never moves.