The timing of shifts of head postures in relation to speech during conservation was investigated by continuously monitoring, with a polarised light goniometer, the head movement of four subjects engaged in conservation. Postural shifts (PSs), defined as wide, linear movements, were found to occur primarily towards the initiation of speech, be it between speaking turns, or between syntactic boundaries inside speaking turns. This suggested that PSs are involved in regulating turn taking and marking syntactic boundaries inside speaking turns. Also, PSs usually started prior to and continued till after speech onset. This suggested a possible involvement in speech production, probably in helping to regulate the complex motor processes of beginning to speak. It is suggested that interactive, linguistic and speech productive functions may combine together to create a movement pattern by mutually constraining head movement.