Descriptive studies of clinician-child therapy interaction suggest a tightly controlled system of verbal exchange centring around the underlying plan of the clinical lesson. Drawing upon examples from therapy lessons, this paper describes the nonverbal component of clinician-client interaction. Nonverbals are associated features of situational context, lesson organization, and remedial sequences; they emphasize, parallel, or replace verbal and nonverbal elements. The clinician uses a wide variety of body mechanisms (e.g. head, face, hands, voice) to support her efforts to facilitate child responses and manage social behaviour. A full understanding of lesson discourse must include observations of nonverbal communication.