"What came first?" He asked. "The changes in the number or the changes in the brain?"
Ray Jackendoff, a linguist at Tufts University who was not involved in the study, said that the group's opinion that it was easy to say some sounds may vary with diet "is interesting but not earthquake." The different cultures may have expressed some sounds more often than others "do not say much about the deep history of the language."
Other cultural and social factors, such as adopting sounds from neighbors, may also have contributed to language changes, the researcher's author said. For example, when hunter-gatherer groups and agricultural groups mixed, so did their sound .
Other language versions also point out that the study rests on untested assumptions, just as how much these small change changes can affect sounds, the types of errors they can produce, the age of the hunter's teeth wear and the idea that agriculture is a useful proxy for diet. Cognitive factors, including neural control of speech organs, also go unaddressed.
The authors answer that they do not minimize the roles that culture, society or cognition play in language development. But they say that physical differences between people deserve so much attention in the study of human language development as they do to investigate animal communication systems.
Some linguists worry that if not handled with extremely careful studies of the physical or biological differences in language, it could strengthen ethnocentric beliefs that have previously plagued linguistics, especially if research is interpreted publicly as valuation judgments by different groups' languages.
"The risk here is a bias to focus on positive benefits or what is achieved by individuals in agricultural communities, rather than considering what benefits individuals in hunter collectors may have," said Adam Albright, a linguist at MIT