The Heritability of Language: a Review and Metaanalysis of Twin, Adoption, and Linkage Studies

Some researchers argue that the ability to acquire and use language is largely the result of innate predispositions that are specific to language (the INNATENESS HYPOTHESIS). If the innateness hypothesis is correct, these predispositions must be encoded for in our DNA. This article reviews more than one hundred genetic studies of language. The results of these studies strongly suggest that genetic factors play a role in the variation in the rate of language acquisition and linguistic proficiency attained by children and adults. Genetic factors account for much of the variance in linguistic abilities among people with written or spoken language disorders and some of the variance in linguistic abilities among normal people. In addition to heritable factors that influence both nonverbal and verbal abilities, there appear to be genetic factors that specifically influence linguistic abilities. Furthermore, some studies suggest that different genetic factors are involved in different aspects of language (e.g. written language vs. spoken language; lexical vs. syntactic abilities).*