Two by two: a twin study of second-language acquisition

Philip S Dale, Nicole Harlaar, Claire M A Haworth, Robert Plomin

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)


In this report, we provide initial results of the first application of the classic twin design to second-language acquisition. The analysis was conducted on assessments teachers made using United Kingdom National Curriculum standards and included 604 pairs of 14-year-old twins. The results demonstrate substantial heritability (.67) and low influence of shared environment (.13) on this measure of second-language acquisition. The heritability of second-language acquisition at 14 years is comparable to the heritability of the two first-language acquisition measures obtained at 12 and 14 years, respectively, and is higher than heritability estimates previously published for first-language acquisition in early childhood. Multivariate behavior genetic analyses suggest very high, but not complete, overlap of genetic influences on first- and second-language acquisition, and less overlap between shared environmental influences on the two domains.

Original languageEnglish
Pages (from-to)635-40
Number of pages6
JournalPsychological Science
Issue number5
Publication statusPublished - May 2010


  • Adolescent
  • Aptitude
  • Child
  • England
  • Female
  • Genetics, Behavioral
  • Humans
  • Language Development
  • Longitudinal Studies
  • Male
  • Multilingualism
  • Social Environment
  • Twins
  • Wales


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