What aDNA can (and cannot) tell us about the emergence of language and speech

The genome sequencing of individuals belonging to extinct forms of the genus Homo has provided us with a detailed view of the genetic makeup of some of our close extinct relatives. In addition, the unprecedented depth of sequencing of modern Homo sapiens populations has given us a framework for interpreting minor changes at the DNA sequence level that are putatively relevant to a broad array of anatomical and behavioral characteristics. Here we discuss the genetic architecture of such complex characteristics, with a special focus on language and speech. We examine the extent of reported variation in the DNA sequences of genes that are thought to be involved in their production, both in H. sapiens populations and in our extinct relatives, and we discuss to what extent such sequence variations are relevant to making direct statements about the capacity of extinct hominids to generate and express language and speech. Because language is a highly complex behavioral character we stress the difficulties involved in using the 'atomized' DNA sequence data as indicators of its possession by extinct hominids, and we emphasize that such data should not be considered in isolation from other relevant information gleaned from comparative anatomy and the archaeological record.