Why populations?

If you have got further than the title, then you are reading a chapter in a book about analysing linguistic variation in English, written by a molecular geneticist, which will be asking whether differences in our genes are relevant to understanding differences in language. Of course, the chapters in this section show that linguistic variation is relevant in all kinds of domains – in legal and educational contexts, for example, and in building speakers' identities – and conversely that those various domains may help us understand more about variation in language, where it has come from, and what it means. Unlikely though it might seem to some, this chapter will explore the possibility that biological or genetic variation falls into the same category of apparently external factors which may cast light on some aspects of linguistic variation.

This idea is not uncontroversial. Some writers on historical linguistics, for instance, regard it as a self-evident truth that genes have nothing whatsoever to do with language; or rather, that while our human genetic make-up might conceivably contribute to our capacity to acquire and use language per se, it certainly has no impact on the specific language or variety we use. Thus, Hale (2007: 226), discussing the generally accepted genetic hypothesis, which proposes that repeated structural similarities in languages today indicate descent from a common ancestor language, suggests that: