Creates a predicate abstraction sumti out of a full bridi clause, binding all the necessary lambda variables to the ko'a-ko'u pronoun series. The number of bound variables must be indicated by appending {xi} followed by that number to the word {fo'ai}, unless only one variable (namely {fo'a}) is bound, in which case the {xi} marking is optional.
Delete all sumti slots of the immediately preceding word which are not explicitly filled excepting the first n (specified by subscript; contextless default: n=0).