This study of four moderately to severely aphasic subjects found that success in manual sign training programs is related to severity of aphasia, that aphasic subjects' propositional use of manual signs rarely follows simple acquisition, and that generalization to untrained stimuli or environments does not occur without additional training.…

Four adults with moderate/severe disabilities were taught to request objects by using the manual signs "want" or "please" plus an object label sign, within the context of familiar activities in which needed objects were missing. All participants acquired a generic requesting response, and three acquired an explicit requesting…