A reader pointed me to this critique of Nick Wades' telling in The New York Times Reports that the recent Reich et al. paper on Native Americans is a vindication of Joseph Greenberg's ideas on the languages of the Americas. 90-Year-Old Consensus:
Nicholas Wade’s reported the Reich et al. research in the New York Times (July 11, 2012). Wade treats it as a vindication of a three-way genetic (historical linguistic) distinction among languages of the Americas proposed in Joseph Greenberg’s (1987) book of the same name, although Reich et al. do not cite it in their paper in Nature. (The only reference to Greenberg by Reich et al. is to a paper coauthored with Turner and Zegura and published in 1986 as one of the proponents of the three-way split.) The “vindication” here is entirely Wade’s. The bottom line is that this three-way distinction was known linguistically since the 1920s (for example, Sapir 1921). Basically, it’s a division among the Eskimo-Aleut languages, which straddle the Bering Straits even today, the Athabaskan languages (which were discovered to be related to a small Siberian language family only within the last few years, not by Greenberg as Wade suggested), and everything else. That’s essentially the three-way distinction that is constantly credited to Greenberg. We know of many major linguistic families among the “everything else”, worked out painstakingly through well-established methods, but don’t know how the “everything else” language families are connected to each other on a large-scale level. ... Let me add that I am skeptical when someone says that a biological genetic grouping corroborates a historical linguistic grouping or vice versa for a simple reason: genetic material and language are transmitted by different mechanisms (I’ll skip my usual joke about this), so in principle a one-to-one correspondence should be surprising.
First, when I first heard about Greenberg's system in the late 1990s I chatted up a few people who were involved in the linguistics of Native Americans on the issue. They thought he was full of it, but, they were also pretty much opposed to imposing any real coarse structure on Native American languages, including the model which is claimed to be pretty well known above. My sample could be very unrepresentative. I'll let readers who know more weigh in (note that I'm skeptical of classifying all the "First American" languages into one group after 15,000 years, even assuming they derive from a common ancestor). On the other hand, the author caricatures the paper which he discusses by suggesting a "one-to-one correspondence." In fact, the two non-First American groups are genetic, but not linguistic, hybrids. Additionally, the argument that cultural and genetic transmission differ is specious. Certainly it is true, but the two are also correlated due to the effect of culture and language on marriage networks. This seems common sense, but many social scientists in my experience seem to recoil from any disciplinary integration with genetics, and so totally distinguish the character of cultural heritability and genetic heritability.