On grammatical class:

ke'a
pro-sumti: relativized sumti (object of relative clause).
ma
pro-sumti: sumti question (what/who/how/why/etc.); appropriately fill in sumti blank.
zi'o
pro-sumti: fills a sumti place, deleting it from selbri place structure;changes selbri semantics.
zo'e
pro-sumti: an elliptical/unspecified value; has some value which makes bridi true.
zu'i
pro-sumti: the typical sumti value for this place in this relationship; affects truth value.
di'au
pro-sumti and sumyzmico: discourse-interior default it (terbri-specific)
di'ei
pro-sumti and sumyzmico: an elliptical/unspecified value which does not necessarily obey the default setting for the corresponding terbri that is explicitly specified in the definition of the word; has some value which makes bridi true
di'oi
pro-sumti & sumyzmico: discourse-exterior default it
mai'i
pro-sumti: the universal argument/value; syntactically-contextually and type-permitted maximally generic in its typing
nau'u
what is now; refers to current space/time/situation reference absolutely
zai'o
pro-sumti: the empty argument/value; syntactically-contextually and type-permitted maximally generic in its typing