Gender and number inflectional morphology in Italian agrammatic speakers: Further evidence for dual route models of processing

This paper summarizes and discusses the results of several morpholexical and morphosyntactic experiments with two Italian patients who showed typical agrammatic features in speech production following neurological damage to the left cerebral hemisphere. Issues addressed in this study are whether the impoverished morphology in the patients' speech is due to impaired morpholexical functioning in general, to specific impairments in the lexical component responsible for regular inflectional morphology, or whether the apparent dysmorphology is the result of an impairment in syntax. The last hypothesis is supported by the data reported in this paper, and more particularly, the breakdown seems to occur if the appropriate morphological realization depends on a linking of thematic roles with coindices. A specific morpholexical impairment was also found with respect to compounds. It is obvious, however, that this impairment cannot account for all agrammatic phenomena in sentence production (e.g., selective impairment of function words).