The phenomenon of unaccusativity is a central focus for the
study of the complex properties of verb classes. The
Unaccusative Hypothesis, first formulated in 1978, claimed that
there are two classes of intransitive verbs, the unaccusative
(Jill arrived) and the unergative or agentive (Jill sings). The
hypothesis has provided a rich context for debating whether
syntactic behaviour is semantically or lexically determined, the
consequence of syntactic context, or a combination of these
factors. No consensus has been reached. This book combines new
approaches to the subject with several papers that have achieved
a significant status even though formally unpublished. Among the
issues the authors address are: the determination of the
unaccusative class of verbs, the problem of unaccusativity
diagnostics, the implications of special morphology for the
structural representation of unaccusatives and the status of the
external thematic role, the properties guiding the unergative
versus unaccusative distinction in acqui