On grammatical class:

ji'a
discursive: additionally.
ku'i
discursive: however/but/in contrast.
mi'u
discursive: ditto.
po'o
discursive: uniquely, only, solely: the only relevant case.
si'a
discursive: similarly.
xa'oi
already; too early than expected;
za'oi
yet; still; too long