Unaccusativity as lexical argument reduction: Evidence from aphasia

Theoretical approaches to unaccusativity have placed an emphasis on their derivation from underlyingly transitive predicates, which is assumed to involve argument reduction, possibly triggered by pre-syntactic affixation of some abstract morpheme. This paper presents some data from an aphasic subject who demonstrates a robust effect of grammatical class; he is unable to read any function words, and makes characteristic ‘within-category’ substitution errors. These errors extend to the class of unaccusative verbs, and this leads to a consideration of the potentially functional nature of the morphological trigger for unaccusativity. Existing accounts of unaccusative deficits in aphasia, and of the likely morphosyntactic representation of unaccusative verbs are discussed. The aphasic deficit, as we understand it, seems to provide evidence in support of the functional determination of unaccusativity.