Part 4 · grammar — Chapter 15 · voice possibility

Necessity na

Where po opens a door, na points at the one door there is. It marks what must be so, and Phi uses a single particle for every flavor of must, trusting context to say which one is speaking:

thia thuroa — "You grow"
thia na thuroa — "You must grow"

The body's needs:

miona na nulae
person NEC sleep
"A person must sleep"

Conclusions the evidence forces. This is na doing inference: you did not see it happen, but what you see now leaves one explanation:

thinoe ki na thuroa
seed PFV NEC grow
"The seeds must have sprouted"

womu ki se na lorima
home PFV PASS NEC build
"The house must have been built" (it stands there, after all)

Obligations circumstances or ethics impose:

lo mia na naphe
PL 1SG NEC help
"We must help"

Notice what the inferential uses share with the evidential ke (Part IV, chapter 16): both admit the speaker is reasoning, not witnessing. na claims the reasoning is airtight; ke claims only that it happened. A careful speaker keeps the two apart, and listeners learn quickly which kind of speaker they are dealing with.

With tense and aspect

na sits in the modal position of the fixed Slot 1 order:

mia to na thalo — "I had to walk"
thia so na shonela — "You will need to learn"
mia si na thalo — "I must be walking" (the necessity is ongoing)
mia ki na kamo — "I must have arrived"

Saying must out loud

An unmarked assertion hides its reasoning; na shows it. When someone says lo mia na naphe, they are not reporting a fact about the world: they are presenting the conclusion of an argument and inviting you to check it. That is the difference between pressure and reasoning made audible, and it is why necessity in Phi tends to start conversations rather than end them.

What must be done is heavy enough. na at least makes sure everyone can see where the weight comes from.