In this chapter, we present the hypothesis that the production of speech had a simple evolutionary origin, and then increased in complexity in particular ways, and that this sequence of events was similar to the one which is observed in speech acquisition. The chapter has three parts. The first is a comparison between speech and other primate call systems to identify changes which occurred in the evolution of speech. The second is a presentation of evidence from sound inventories of existing languages which suggests that speech systems have indeed increased in complexity since the advent of the first speechlike forms. Finally, we examine speech acquisition to infer in some detail what the initial patterns of speech might have been like and what forms the subsequent increases in complexity might have taken.

Basic to the present approach is the axiom that whenever a versatile movement repertoire is present in an animal, the capability for it must have been tinkered into place by evolution. In the absence of a fossil record, the ability to produce the complex movement sequences of speech appears, like the rest of language, to have evolved ‘out of the blue’, thus constituting a ‘continuity paradox’ in the words of Bickerton (1990: 7), as Darwin's theory is antithetical to de novo evolution. The task here is to understand how the movement versatility in speech was tinkered into place so as to give the appearance of discontinuity, in the absence of a fossil record of speech.