This book presents a current, interdisciplinary perspective on language requisites from both a biological/comparative perspective and from a developmental/learning perspective. Perspectives regarding language and language acquisition are advanced by scientists of various backgrounds -- speech, hearing, developmental psychology, comparative psychology, and language intervention. This unique volume searches for a rational interface between findings and perspectives generated by language studies with humans and with chimpanzees. Intended to render a reconsideration as to the essence of language and the requisites to its acquisition, it also provides readers with perspectives defined by various revisionists who hold that language might be other than the consequence of a mutation unique to humans and might, fundamentally, not be limited to speech.