title: Two by two: a twin study of second-language acquisition.
abstract: 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.
authors.affiliation: Department of Speech and Hearing Sciences, University of New Mexico, 1700 Lomas Blvd. NE, Albuquerque, NM 87131. dalep@unm.edu
authors.forename: Philip S
authors.initials: PS
authors.lastname: Dale
authors.forename: Nicole
authors.initials: N
authors.lastname: Harlaar
authors.forename: Claire M A
authors.initials: CM
authors.lastname: Haworth
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
mesh_terms: D000293:Adolescent; D001076:Aptitude; D002648:Child; D004739:England; D005260:Female; D005824:Genetics, Behavioral; D006801:Humans; D007804:Language Development; D008137:Longitudinal Studies; D008297:Male; D019303:Multilingualism; D012931:Social Environment; D014427:Twins / Q000235:genetics* / Q000523:psychology; D014852:Wales