Abstract: This book uses evidence from and about sign languages to explore the origins of language as we know it today. According to the model presented in this book, it is sign, not spoken languages, that is the original mode of human communication. The book demonstrates that modern language is derived from practical actions and gestures that were increasingly recognized as having the potential to represent and hence to communicate. In other words, the fundamental ability that allows us to use language is our ability to use pictures of icons, rather than linguistic symbols. Evidence from the human fossil record supports the book's claim by showing that we were anatomically able to produce gestures and signs before we were able to speak fluently. Although speech evolved later as a secondary linguistic communication device that eventually replaced sign language as the primary mode of communication, speech has never entirely replaced signs and gestures.

Keywords: sign language, human communication, actions, gestures, icons, pictures, symbols, speech