Two patients with mixed transcortical aphasia could repeat propositional speech but not affective prosody. These findings suggest that the intact perisylvian region responsible for propositional speech does not mediate affective prosody. We propose that affective prosody is incorporated into propositional speech by means of an interhemispheric mechanism and that the failure of these patients to repeat affective prosody was caused by a disconnection of the left perisylvian structures from the right hemisphere structures thought to mediate affective prosody. © 1984, American Medical Association. All rights reserved.