On grammatical class:

di'i
tense interval modifier: regularly; subjective tense/modal; defaults as time tense.
na'o
tense interval modifier: characteristically/typically; tense/modal; defaults as time tense.
ru'i
tense interval modifier: continuously; subjective tense/modal; defaults as time tense.
ta'e
tense interval modifier: habitually; subjective tense/modal; defaults as time tense.
di'inai
tense interval modifier: irregularly/aperiodically; tense/modal; defaults as time tense.
na'onai
tense interval modifier: atypically; subjective tense/modal; defaults as time tense.
ru'inai
tense interval modifier: occasional/intermittent/discontinuous; defaults as time tense.
ta'enai
tense interval modifier: non-habitually; subjective tense/modal; defaults as time tense.