Using both theoretical and language acquisition arguments, this study proposes a new model of the lexicon-syntax interface defined in terms of checking event-semantic features. The research is based on Dutch verbs and their possible verb frames (intransitive, transitive, etc.) and two studies of children's Dutch. The model developed from these cases represents more generally the way in which Universal Grammar organizes the lexicon of a language and the mapping system that associates a verb's lexical features with its syntactic projection. The author shows that a predicate's event-semantic or aspectual properties define the mapping relation between lexicon and syntax, rather than lexical-semantic information of the verb's event participants, which is the more traditional view. A verb's appearance in several different verb frames is determined by event type-shifting; an atelic (= unbounded) or a telic (= bounded) event type yields different verb frames, and so does a non-causative or a causative event type. These effects can only be captured if the mapping relation is sensitive to event semantics. The two acquisition studies offer a new and unique perspective on verb learning. One is a longitudinal study on the acquisition of light verbs; the other is an experimental study on the acquisition of intransitive verbs. They show that children are sensitive to event semantics from early in the language acquisition process.