Twin study on Chinese language and reading development

Abstract

This study investigates the relative contributions of genetic and environmental influences on Chinese language and reading development in 150 pairs of monozygotic and 150 pairs of same-sex dizygotic twins. Typically developing twin pairs aged from 4 to 11 were recruited in Hong Kong local kindergartens and primary schools. They were tested individually on tasks of character recognition, receptive vocabulary, phonological processing skills, tone awareness, morphological awareness, orthographic skills, and general cognitive abilities. Also, their saliva was collected for zygosity assessment, and their parents were required to fill in a questionnaire to provide information on family background, and home literacy environment. Testing was completed in November 2008, and data analysis using Mx will have been done by March 2009. Variances of each construct explained by genetic, shared environmental, and non-shared environmental influences will be computed, and genetic correlations among constructs will be explored. It is hypothesized that heredity will play a more central role on reading skill and phonological awareness, while environment will have relatively stronger effects on vocabulary knowledge and orthographic skills, in learning Chinese. However, we anticipate a smaller genetic effect on Chinese reading skill compared to past studies on English. This study is the first twin study of learning Chinese, a language which has contrasting characteristics with alphabetic languages. It will be key to enhancing the understanding of universal or specific factors of language and reading acquisition across languages, and will inform educational policy on the construction of effective learning environments for Chinese acquisition.