Linguistic processing factors affecting aphasic subjects sentence production are to be studied, with the aim of determining whether the predicted computational load aids in understanding success and failure in production. The emphasis is on 4 specific issues: 1) number of alternative verb argument structures that are permissible. 2) processing load introduced by constituent movement. 3) degree of constraint, limiting subjects choice of structures. 4) effect of syntactic processing on lexical retrieval. The effects of these factors are to be examined in a sample of at least 50 aphasic subjects who have recovered at lease 2-word propositional utterances, and differential effects as a function of type of aphasia will be examined. Sentences will be elicited by means of pictures o actions among two or three persons or objects, scored and analyzed in terms of correctness and errors of specific types. The lexical retrieval issue will be investigated by comparing subjects' success in a picture-naming test composed of all the objects in the sentences with their retrieval of the identical words in sentence context.
