This book proposes a step-by-step process by which the early evolution of human language originated. Starting from an ape-like communication system, pre-human ancestors were "pumped" out of the rainforest by cyclic climate changes between 10 and 6 Mya and subjected to harsh predatory conditions and the absence of safe havens. A phonetic "modal voice" evolved in response. Inarticulate sounds gradually became articulated syllables. The diversification of these syllables eventually led to symbolic references and then finally to words. Bancel details each of these steps in which the origin of language and the origin of humans were concordant.