Thirty-two subjects (5 Broca's, 7 conduction, and 10 anomic aphasics and 10 normal controls) performed story retell and procedural discourse tasks containing familiar and unfamiliar topics, with familiar and unfamiliar listeners. Results indicated that topic familiarity significantly influenced verbal output in both normal and aphasic subjects. Specific findings differed, however, depending on type of task. (Author/JDD)