Dale, P.S., Harlaar, N., Hayiou-Thomas, M., & Plomin, R. (2010). The Etiology of Diverse Receptive Language Skills at 12 Years. Journal of Speech, Language, and Hearing Research, 53, 982-992.
Substantial research has been conducted on earlier but not later stages of language development. Early child language research is not transferable, nor can it be applied to adolescents because of the large increase of qualitative and quantitative language skills that are developed, and continue to develop. Along with linguistic changes (e.g., lexicon, verbal reasoning, syntax, pragmatics, figurative language and literacy), there are consequential changes in cognition, academia and social experiences.
To study the etiology of language skills at 12 years of age, Dale et al. (2010) conducted a twin study (n = 4,892) comparing performance of twins with identical genetic complements (monozygotic) and those with differing genetic complements (dizygotic). Greater relationships between measures for the monozygotic vs. dizygotic twins reflect genetic contributions. The researchers measured vocabulary, listening grammar, figurative language, and making inferences using online measures.
A factor analysis revealed that all four language measures loaded on the same factor, a single language factor. Not surprisingly, genetics and shared environment both influenced these factors. As well, there were no significant differences between boys and girls that underlie the etiology of language development. These findings are also consistent with the generalist genes hypothesis.
This study employed a well-accepted research paradigm (twin study) with a large sample. The findings that genetics and environment contribute to language are consistent with current clinical and research views. The results of one language factor incorporating vocabulary, receptive grammar, figurative language, and making inferences suggests that improvements in one of these areas should lead to improvements in the other areas.
Blogger: Sarah Cloutier. Sarah is completing her Masters degree in Child and Youth Health, Health and Rehabilitation Sciences at The University of Western Ontario. She is studying behavioural measures of parent abilities, and familial and environmental factors that influence a broad spectrum of children and their language abilities. Sarah had also been a research assistant in the Language and Working Memory Lab with Dr. Lisa Archibald.