Abstract A striking fact about Mohawk polysynthetic observed in chapter l is that although it puts great emphasis on agreement and noun incorporation, certain other kinds of morphological structures arc relatively restricted. Mohawk does not have the diversity of “ complex predicate” constructions that some languages have, and, more importantly, some of those that it does have are restricted in their use. Moreover, similar restrictions appear to a greater or lesser degree in other polysynthetic languages as well. This observation goes against the conventional wisdom about polysynthetic languages, which is that they can express virtually any standard linguistic relationship by morphological means. In fact, the theoretical maximum of morphological complexity seems not to be reached. Rather, those languages that are rich in noun incorporation are poor(er) in other complex predicates, and those that are rich(er) in complex predicates are poor in noun incorporation.