On grammatical class:

fy'oi
Number suffix initiating a subordinate clause representing a predicate whose arity is the suffixed number; the lambda variables representing the predicate slots are bound from the fo'a-fo'u series in their dictionary ordering; the number of bound variables is the same as the predicate arity.
ky'oi
Number suffix initiating a subordinate clause representing a predicate whose arity is the suffixed number; the lambda variables representing the predicate slots are bound from the ko'a-ko'u series in their dictionary ordering; the number of bound variables is the same as the predicate arity.