Morphological processing in Italian agrammatic speakers syntactic implementation of inflectional morphology

Most current linguistic and psycholinguistic characterizations of agrammatic production start from the observation that in spontaneous speech inflectional suffixes are either dropped or substituted by default forms, depending on the morphological structure of the language. So far, little experimental evidence has entered theory construction. In this paper, elicited data of two Italian patients with agrammatic speech are presented. The tasks involved the production of a past participle suffix in different sentence contexts. In Italian, the past participle has to agree in gender and number with the grammatical features of an antecedent noun, pronoun, or empty element. It is shown that both patients mastered the general principles of the agreement rule, and that they could produce correct inflectional suffixes in several tasks. Furthermore, the point of breakdown in their performance was syntactic rather than morphological, namely, when there were no overt morphological cues for the identification of the thematic roles in the sentence. These data cannot be accounted for by theories formulated in terms of the syntactic or postsyntactic deletion of suffixes or the functional elements underlying their realization. At least for the patients in this study, morphological substitutions arose as a result of an impairment in the syntactic processing of content words rather than functors.