Storage or parsing of morphologically complex words? The processing of inflectional and derivational morphology in an Italian agrammatic patient

We analyzed the performance of a patient (M.B.) affected by agrammatism and phonological dyslexia. M.B. was tested with a series of tasks requiring lexical retrieval of simple and morphologically complex words. The patient presented a pattern of errors that is interpreted as the result of the prominent use of the lexical routine. This pattern of errors was characterized by frequency effect more than by a difference between types of suffixes (inflectional versus derivational) or types of word. It seems that high-frequency morphologically complex items will meet stored representations, thus avoiding more costly parsing that is required for less frequent items. These results are in keeping with dual-route models of lexical representation of morphologically complex words.