Well, it’s my bounden duty to tell you about the latest theory of language spread, but I’m damned if I know what to say. According to an article by Nicholas Wade in today’s NY Times, Jared Diamond of the University of California at Los Angeles and Peter Bellwood of the Australian National University in Canberra are claiming that the world’s languages were spread by agriculture.
The premise is that when humans lived as hunters and gatherers, their populations were small, because wild game and berries can support only so many people. But after an agriculture system was devised, populations expanded, displacing the hunter-gatherers around them and taking their language with them.
On this theory, whatever language happened to be spoken in a region where a crop plant was domesticated expanded along with the farmers who spoke it.
Even if the farmers interbred with the hunter-gatherers whose land they took over, genes can mix, but languages cannot. So the hunter-gatherers would in many cases have adopted the farmers’ language. That is why languages “record these processes of demographic expansion more clearly than the genes,” Dr. Bellwood said.
Aside from the usual Times quota of misstatements (Bantu is not the same thing as Niger-Congo) and presentation of hypotheses as fact (“The founder language [of Austronesian] was spoken by rice growers in southern China”), the piece—and I presume the original Science article—is full of “may have” and other warning signals. Cautionary voices are left till almost the end of the article (“Dr. Christopher Ehret of U.C.L.A., an expert in the history of African languages, said the authors had overstated the role of agriculture in explaining the pattern of language distribution”). Neither of the authors is a linguist (Diamond is a physiologist, Bellwood an archaeologist), and they naturally accept whatever linguistic theories best fit the story they want to tell. But my main reaction is: so? This theory is not blatantly silly, like the genetic click one the Times was excited about a few weeks ago (they seem to have forgotten all about it, since they mention “the Khoisan, or click-language speakers” without reference to their unique genetic heritage), but there’s no way of knowing how true it is, and what good is yet another unprovable theory? Call me small-minded, but I’d rather have one honest fact pried from the great blooming, buzzing confusion of the world than a dozen ambitious but untestable hypotheses.