The term “gesture” is used to denote various human actions. This is even true among linguists and psychologists, who for the past two decades or more have highlighted the importance of gestures of various sorts and their significant role in language production and reception. Some writers have defined gestures as the movements of the hands and arms that accompany speech. Others refer to the articulatory movements of speech as vocal gestures and those of signed languages as manual gestures. For those who work in signed languages, the term nonmanual gesture usually refers to facial expressions, head and torso movements, and eye gaze, all of which are vital parts of signed messages. In the study of child language acquisition, some authors have referred to an infant's reaches, points, and waves as prelinguistic gesture.

In Part II we introduce two works that highlight the importance of the study of gesture and one that addresses iconicity (a closely related topic). We also briefly summarize some of the various ways in which gesture has been defined and investigated over the last decade. A few pages of introductory text are not enough to review all the issues that have arisen – especially within the last few years – concerning gesture and iconicity and their role in language, but this introduction is intended to give the reader an idea of the breadth and complexity of these topics.