Human beings gesture everyday while speaking: they move their hands, their heads, their arms; their whole body is involved in communication. But how does it work? How do we produce gestures and in what purpose? How are gestures connected to speech? When do we begin producing gestures and how do they evolve throughout the life span? These are questions gesture researchers have been trying to answer since the second half of the 20th century.
This chapter will first define what a gesture is by describing the different kinds of gestures and by explaining some of the current theories about gesture production. Then, the emergence of gesture along with language development will be exposed as well as its evolution during childhood. Finally, we will review studies about adults' gestures and what we know about their change across adulthood.