Bilingualism and Cognitive Development

Research on the effects of bilingualism on cognitive development is reviewed, and two complementary models of bilingualism are developed to account for research results. It is suggested that research since 1960 shows a positive relationship between bilingualism and cognitive development, at least for some types of bilingualism. The advantage or disadvantage of becoming bilingual seems to depend on the way a subject becomes bilingual and the degree of language proficiency achieved. The "S-curve" model deals with the effects of the environment in the development of a bilingual's cognitive abilities. The second model, a bilingual's cognitive structure model, explains how different types of bilingualism are developed and why some types of bilingualism are expected to result in cognitive advantages. It is concluded that the advantage of being a coordinate bilingual (i.e., one exposed to two languages at a very early age who learns two distinct coding systems) is due to the bilingual's capacity to use language independent relations as well as relations between concepts unique to the two languages. There is no evidence that compound bilingualism (i.e., learning the second language through translation from the dominant language) will lead to cognitive advantages, while a major influence on the outcome seems to be the age of initial exposure to the second language. The social context in which the bilingual develops is also very important in determining the final outcome. (SW)