Blute Blog

I was rather cautious in Darwinian Sociocultural Evolution about the possible existence of a “mother tongue” of all human languages (sometimes called “proto-world” or “proto-sapiens”). I would be less inclined to be so today on the basis of the genomic evidence for our “recent out-of-Africa” origin.

About 50,000 years ago one or at most two small groups of anatomically and behaviourally modern humans Homo sapiens sapiens (perhaps only 150 or so individuals and probably speaking a language with many phonemes, many of them “click” sounds of various kinds) migrated out of Africa, stimulated possibly by climate change. By 10,000 years ago or so  i.e. in only 40,000 years, through subsequent repeated migrations, their descendants had spread out to displace earlier migrants, to inhabit the furthest reaches of all continents except Antarctica, and to eventually give rise to the named cultures and languages of the anthropological literature.  That is the story that has emerged from the human genomic evidence gathered and analyzed initially by Luigi Cavalli-Sforza of Stanford University and subsequently by Spencer Wells and associates in The Genographic Project among others (for accessible treatments see Wade 2007, Wells 2007).

Because specific languages (albeit not the capacity for language) is acquired socioculturally, the implication of these findings is that all human languages on earth today have descended with modification socioculturally from one or two common ancestral languages. Since no one thinks it possible that language evolved later than 50,000 years ago and some think much earlier, that is the inescapable conclusion from the genomic evidence – unless one wished to argue that one or more groups stopped talking for some generations and then began anew again which seems most unlikely.

I will add immediately that this conclusion cannot be drawn directly from the linguistic evidence – language does changes rapidly on this time scale of tens of thousands of years and phylogenetic signals eventually get lost. Historical linguists therefore tend to argue that while this story may be true, we will never know for sure. Others however think it more prudent to say “never say never in science”.  In the meantime, cultural descent with modification including of languages is consistent with what we know on smaller but still large temporal and spatial scales – the some 200 language families within each of which the languages can be shown on linguistic grounds to be historically related by common descent. The large Indo-European family of course was known even in Darwin’s time who used it as an analogy for his biological theory of descent with modification. There are at least some cases in which these language families in turn have been shown to be historically related. And of course there is similar research on other areas of culture such as social organization and material culture (both prehistoric i.e. archaeological and historic).