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Is our style of language in our genes?

May 28, 2007
Special to World Science  

Dif­fer­ences in our genes in­flu­ence the type of lan­guage we speak, lin­guists re­port. 

“Ton­al” lan­guages such as Chin­ese use pitch changes to con­vey the mean­ing of words, while non-ton­al lan­guages such as Eng­lish don’t. 

Dan Dediu and Rob­ert Ladd of the Un­ivers­ity of Ed­in­burgh, Scot­land, found that groups of peo­ple who car­ry re­cently evolved ver­sions of two genes tend to speak non-ton­al lan­guages. The genes, be­lieved to af­fect brain de­vel­op­ment, are called ASPM and Mi­cro­ce­pha­lin. 

The newer ver­sion of ASPM ap­peared an es­ti­mat­ed 5,800 years ago; Mi­cro­ce­pha­lin most re­cently changed about 37,000 years ago. The two are among a va­ri­e­ty of genes that have changed re­cently in hu­man evo­lu­tion—part of what one re­cent study has called a trend of quickly ac­cel­er­at­ing ev­o­lu­tion in hu­mans.

Dediu and Ladd cal­cu­lat­ed sta­tis­ti­cal links be­tween 983 loca­t­ions in the ge­nome and 26 dif­fer­ent lin­guis­tic fea­tures in 49 dis­tinct popula­t­ions from around the Old World. They found that there is gen­er­ally no link be­tween genes and lan­guage fea­tures. But when bi­ases for ge­og­ra­phy and his­to­ry were re­moved, a pat­tern emerged be­tween in which ton­al lan­guage speak­ers lacked the more re­cently evolved forms of ASPM and Mi­cro­ce­pha­lin.

The gene-lan­guage rela­t­ion­ship in this case “can­not be ex­plained by his­tor­i­cal and geo­graph­i­cal fac­tors, thus strength­en­ing the claim of a caus­al rela­t­ion­ship be­tween them,” the re­search­ers wrote in this week’s early on­line is­sue of the re­search jour­nal Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces. 

The study in­tro­duces a new meth­od­ol­o­gy “for stu­dying the rela­t­ion­ship be­tween ge­net­ic and lin­guis­tic di­vers­i­ties,” they wrote. They added that they hope fu­ture ex­pe­ri­ments will re­veal how these genes in­flu­ence in­di­vid­ual brains and, ul­ti­mate­ly, the lan­guage pref­er­ences of whole popula­t­ions.

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Differences in our genes influence the type of language we speak, linguists report. “Tonal” languages such as Chinese use pitch changes to convey the meaning of words, while non-tonal languages such as English don’t. Dan Dediu and Robert Ladd of the University of Edinburgh found that groups of people who carry recently evolved versions of two genes tend to speak non-tonal languages. The genes, believed to affect brain development, are called ASPM and Microcephalin. The newer version of ASPM appeared an estimated 5,800 years ago, and Microcephalin was most recently modified about 37,000 years ago. The two are among a variety of genes that have changed recently in human evolution—part of what one recent study has called a trend of accelerating evolution in humans. Dediu and Ladd calculated correlations between 983 locations in the genome and 26 different linguistic features in 49 distinct populations from around the Old World. They found that there is generally no link between genes and language features; but when biases for geography and history were removed, a pattern emerged between in which tonal language speakers lacked the more recently evolved forms of ASPM and Microcephalin. The gene-language relationship in this case “cannot be explained by historical and geographical factors, thus strengthening the claim of a causal relationship between them,” the researchers wrote in this week’s early online issue of the research journal pnas. The study introduces a new methodology “for studying the relationship between genetic and linguistic diversities,” they wrote. They added that they hope future experiments will reveal the path by which these genes exert their influence on individual brains and, ultimately, on the language preferences of entire populations.