This book presents a syntactic analysis of predicate types in Spanish and English and two psycholinguistic experiments on unaccusativity in these languages. Assuming the minimalist framework (Chomsky, 1995), Sanz proposes a parametric account of how event types are syntactically and morphologically encoded in Spanish and English. In chapter 1, Sanz argues that unaccusative verbs and other predicate types (transitive and unergatives) map onto different action types (activities, accomplishments, achievements, and states) in phrase structure. These event types, or Aktionsart, are encoded in the features of a functional projection Event Phrase. The features of this projection vary in Spanish and English. In Spanish, the projection has uninterpretable features and interpretable telicity features, which are checked overtly in the syntax by the clitic se, as in constructions like Juan se tomó una cerveza “Juan drank a beer” or El barco se hundió “The boat sank.” In English, the Event Phrase lacks uninterpretable features. Consequently, it has semantic content but is syntactically inactive. English calculates telicity in a projection within the VP called Transitive Phrase, where the features [±measure] are checked.