discursive: yes (overriding) - yes (repeating) - no (overriding). Affirmative / negative.
«toi'u» turns a negative question into a positive. «toi'ucu'i» affirms what was said (Is it true? It is true. Is it not true? It is not true). «toi'unai» states the negative; if the subject or question was negative then it is repeated. «toi'u»'s scale does not negate what was said; for that see foi'acu'i. toi'u and foi'a can be applicable from a classical (as opposed to constructive) math point of view. See also: go'i, je'u, jetnu, ja'i, na'i.