Imagine a child who has never seen or heard any language at all. Would such a child be able to invent a language on her own? Despite what one might guess, the children described in this book make it clear that the answer to this question is 'yes'. The children are congenitally deaf and cannot learn the spoken language that surrounds them. In addition, they have not yet been exposed to sign language, either by their hearing parents or their oral schools. Nevertheless, the children use their hands to communicate - they gesture - and those gestures take on many of the forms and functions of...