Cognitive development of bilingual children

There has always been a common-sense view that the number of languages that children learn, whether through natural exposure or educational intervention, has consequences for their development. The assumption was that these consequences were potentially damaging. Even now, after approximately 50 years of research on the topic, parents remain concerned about their children's development when it includes a bilingual experience. It is now clear that although parents were correct that speaking more than one language has consequences, the assumption about the nature of these consequences is not: the outcome of the experience is in fact the opposite of what many early researchers claimed and what many contemporary parents intuitively believe. In contrast to early warnings about negative consequences, bilingualism turns out to be an experience that benefits many aspects of children's development. Although there are documented delays in acquiring some formal aspects of each language, such as vocabulary (Bialystok 2010), bilingualism has either no effect (intelligence) or positive effects (metalinguistic awareness, cognitive development) on development.