HENRY

 There’s a new paper out soon in P.N.A.S. that I’m betting will cause a bit of a stir. The paper by Dediu and Ladd, apparently shows that tonal languages like Chinese, Thai and Yoruba, are correlated with the certain derived forms of two genes thought to underlie complex cognition in humans; ASPM and Microcephalin.

The New Scientist says:

Using statistical analysis, the pair showed that people in regions where non-tonal languages are spoken are more likely to carry different, more recently evolved forms of two brain development genes, ASPM and Microcephalin, than people in tonal regions. Dediu and Ladd accounted for geography and history, and the gene differences remained.

The authors of the paper have a website where they provide more information: Linguistic tone is related to the population frequency of the adaptive haplogroups of two brain size genes, ASPM and Microcephalin.

Update: P.N.A.S. has de-embargoed the paper (DOI):

The correlations between interpopulation genetic and linguistic diversities are mostly noncausal (spurious), being due to historical processes and geographical factors that shape them in similar ways. Studies of such correlations usually consider allele frequencies and linguistic groupings (dialects, languages, linguistic families or phyla), sometimes controlling for geographic, topographic, or ecological factors. Here, we consider the relation between allele frequencies and linguistic typological features. Specifically, we focus on the derived haplogroups of the brain growth and development-related genes ASPM and Microcephalin, which show signs of natural selection and a marked geographic structure, and on linguistic tone, the use of voice pitch to convey lexical or grammatical distinctions. We hypothesize that there is a relationship between the population frequency of these two alleles and the presence of linguistic tone and test this hypothesis relative to a large database (983 alleles and 26 linguistic features in 49 populations), showing that it is not due to the usual explanatory factors represented by geography and history. The relationship between genetic and linguistic diversity in this case may be causal: certain alleles can bias language acquisition or processing and thereby influence the trajectory of language change through iterated cultural transmission.

Posted on May 29th, 2007 by Simon Greenhill