When did humans first begin to speak, which speech sounds were uttered first, and when did language evolve from those humble beginnings? These questions have long fascinated people, especially in tracing the evolution of modern humans and what makes us different from other animals. George Poulos has spent most of his academic career researching the phonetic and linguistic structures of African languages. In his latest book, "On the Origins of Human Speech and Language," he proposes new timelines for the origins of language. We asked him about his findings.