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.
"lo ka ce'u ce'u ce'u broda (ku)" = "fo'ai xi ci fo'a fo'e fo'i broda (ku'au)". In the rare cases where more than five lambda variables are needed, fo'a xi PA might be used. See also ko'ai, ce'ai.