The Mohawk tense-mood-aspect system has many “irregularities” that seem to require a powerful morphological component distinct from syntax. Nevertheless, it is shown that most of these “irregularities” can be explained in syntactic and semantic terms, once the right lexical entries are given. This result is achieved by making two assumptions of general interest: (1) mood is analyzed as the verbal equivalent of specifity in the NP system, and (2) habitual and stative verbs are shown to have time arguments, whereas ordinary eventive verbs have only event arguments. Given this, morpheme positions, cooccurrence restrictions, and the lack of recursion in the inflectional system can be derived from ordinary principles of composition, head movement, and a simple form of blocking. Only the selection of allomorphs is left to a post-syntactic morphology.