At present, the enquiry into gesture has reached its maturity as a branch of study which endorses a multidisciplinary approach to communication. Notwithstanding its spread into a great number of sciences (Psychology, Psycholinguistics, Ethnology, among others), in recent times little attention has been paid to the phenomena involved, as far as the linguistic point of view is concerned. In particular, the communicative function of gesture has not been addressed enough from a strictly linguistic point of view.

The aim of the present volume is to exploit some methodological instruments provided by Linguistics in order to restore gesture to its original perview within the field. Such a project implies the use of those empirical methodological tools to which psychologists (and also linguists) are familiar. In doing so, the data presented here are analysed as pieces of information that describe behaviour, that are also an integral part of the more complex phenomenon of human communication. To the extent that a study of this kind deals with gesture, a number of theoretical linguistic questions must be resolved.

The major claim of this book is that gesture and speech share the same cognitive, psychological and physiological roots. In fact, gesture will here be claimed to be integral to human language, its function within human communication being as much goal-directed (MacKay, 1972) – and, subsequently, communicative – as speech.

Evidence for this assumption is provided by means of experiments on hearing and deaf subjects, in addition to a review of the major findings about the use and function of gesture in situations of handicap, such as aphasia and blindness. The ideas proposed here are result of a long speculation on the role of gesture in communicative acts, on the one hand, and with respect to language, on the other hand, matured during the decade of my professorship in Non-Verbal Communication, which began at the University of Pavia, and is now continuing at both national and international levels.