Abstract
This paper explores some conceptual and descriptive parallels between vocal and non‐vocal communication, paying particular attention to the physical phenomena and semiotic functions in both speech and gesture. The discussion focuses on the interplay between organic and performance components of speech and gestural behaviour. A central thesis of the paper is that dilemmas of semiotic attribution are likely to arise when a person's organic state constrains or alters their communicative behaviour, especially if the listener or observer is unaware of that organic state. This thesis is illustrated by a discussion of the changes in communicative behaviour that may result from the physical modifications and movement constraints that are typically associated with old age or with selected disorders of movement. The paper concludes that a more integrated programme of research into comparable descriptive and theoretical concepts would offer a timely and fresh perspective on both speech and gesture, and their semiotic role in conversational interaction.