Evolving speech

In the previous chapters I first concluded that the vocal periphery, long emphasized in discussions of language evolution, played a minor role in the evolution of speech. A language-equipped brain could master, and communicate using, the vocal tract of a chimpanzee, or indeed a dog, quite adequately. Furthermore, the flexibility of the vocal apparatus attested in living mammals indicates that there is little hope of reconstructing the speech abilities of extinct hominids from their fossil remains. Finally, the discovery that several animal species possess a reconfigured vocal tract similar to our own, but do not use it in speech production, means that even if we could use fossils to determine when the larynx descended in hominid evolution, we could not necessarily deduce whether those hominids spoke. These relatively negative conclusions supported the positive conclusion that changes in the brain were crucial for the evolution of speech, and we then explored the neural and genetic bases that currently seem to be critical for vocal learning and imitation.

In this chapter, I will attempt to synthesize these diverse strands of evidence, and begin to investigate theories of the evolution of speech and basic phonology. I begin by considering models of speech evolution (often termed “theories,” despite lacking the gravitas normally associated with this term in science). My goal will be to evaluate the central innovations and insights in each model.