The breakdown of functional categories and the economy of derivation.

In this paper I argue that in a hierarchical structure of a sentence, the lower the position of the functional head and its projection, the more accessible they are to an agrammatic aphasic. The major empirical basis for this includes spontaneous speech data and an acceptability judgment experiment by Japanese agrammatic patients as well as the available French and Italian data. The previous cross-linguistic agrammatic data from verb second languages are also examined. The unified account for the status of functional categories in agrammatism is presented based on the principles of the Economy of the Minimalist framework (Chomsky 1994). Finally, the empirical consequences of agrammatic data for language acquisition are discussed.