The interface between bilingual development and specific language impairment

Research at the interface of bilingual development and child language disorders has increased greatly in the past decade. The purpose of this article is to highlight the theoretical and clinical implications of this research. Studies examining the similarities in linguistic characteristics between typically developing sequential bilingual children and monolingual children with specific language impairment (SLI) the same age are reviewed in light of predictions from a maturational model of SLI. Studies examining the linguistic characteristics of bilingual children with SLI compared to monolinguals with SLI and their bilingual peers with typical development are reviewed in light of predictions of limited processing capacity theories of SLI. It is shown that data from bilingual children pose interesting challenges to both theoretical perspectives, although in different ways. Finally, the findings from this research are discussed in terms of their relevance for assessment of SLI in bilingual children. In Canada, 20.1% of the population speaks a language other than French or English at home, and 16 to 36% of 5to 9-year-old children in large urban centers speak a language other than English or French as their first language (L1), and thus are attending school in a second language (L2; Statistics Canada, http://www.statcan.ca). In the predominantly French-speaking province of Québec, 35.8% of francophones also speak English, and 68.8% of anglophones also speak French; bilingualism among francophones in other regions of the country averages 83.6% (Statistics Canada, http://www.statcan.ca). The linguistically diverse Canadian context is not out of step with many other countries (e.g., Goldstein, 2004; Organization for Economic Co-operation and Development, 2006), and it has been estimated that children who learn two languages before puberty are the majority worldwide (Tucker, 1998). Therefore, research at the interface of bilingual development and child language disorders would be relevant to a significant number of children across the globe. However, until recently, bilingual development and child language disorders have been mainly investigated in isolation of each other. The purpose of © Cambridge University Press, 2010 0142-7164/10 $15.00 APS aps99037 January 21, 2010 3:21 Applied Psycholinguistics 31:2 4 Paradis: Interface between bilingual development and SLI this article is to review research in the past decade taking place at this interface. One area of investigation is concerned with the overlap in linguistic characteristics between bilingual children with typical language development (TLD) and monolingual children with specific language impairment (SLI) the same age. Another area of investigation is focused on documenting the linguistic characteristics of bilingual children with SLI, as referenced to their monolingual peers with SLI, and to their bilingual peers with TLD. It will be shown that these studies on bilingual children bring unique and important evidence to bear on theoretical debates regarding the nature of SLI, and contribute much needed information for the appropriate identification of SLI in linguistically diverse social contexts. DEFINING BILINGUAL DEVELOPMENT AND SLI Bilingual development Although all bilingual children, by definition, learn two languages, there are differences in their exposure patterns to both languages and in the social contexts in which they are learning those languages that influence their development. Researchers often make a distinction between simultaneous and sequential bilinguals (L2 learners). Simultaneous bilinguals are children who learn both languages in the home or through early childcare experiences before the age of 3 years, 0 months (3;0), often from birth. Sequential bilingual/L2 children have the L1 fairly established (although not completely acquired) before they begin to learn the L2. Although the division between simultaneous and sequential bilingualism is most often set at 3;0 by researchers (Genesee, Paradis, & Crago, 2004), it is common for sequential bilinguals to begin learning the L2 at school entry, for example, children from immigrant families who speak a minority language at home and learn the majority language at school. In addition, young bilingual children, both simultaneous and sequential, tend to be more proficient or dominant in one of their languages. The dominant language is usually the language for which they have received the greatest amount of exposure (Genesee et al., 2004). The dominant language can shift over time such that sequential bilingual children often end up dominant in their L2 when the L2 is the majority language (Kohnert, 2004). Therefore, a group of 7-year-old bilingual children who speak the same two languages could differ from each other in several respects: in how much exposure they have had to each of their languages, in their acquisition onset age for each language, and in which of their languages is dominant. All of these factors could influence their linguistic performance in both languages. The distinction between the majority/minority sociolinguistic status of a bilingual’s two languages is another relevant distinction to make. Children who speak a majority language at home, like English in Canada, and learn French as an L2 through schooling, would have different projected language outcomes for their two languages than children whose L1 is a minority language, like Tagalog, and who learn English as an L2 at school (Genesee et al., 2004). Most notably, the minority L1 children would be at risk for incomplete acquisition and/or loss of their L1, whereas the majority L1 children would not. In contrast, when the two languages APS aps99037 January 21, 2010 3:21 Applied Psycholinguistics 31:2 5 Paradis: Interface between bilingual development and SLI of a bilingual child are majority languages, like French and English in Canada, whether the child learns them simultaneously or sequentially, successful bilingual outcomes are highly likely because both languages are widely spoken, valued by the society, and institutionally supported through government and the education system. The minority–majority status of languages is really a continuum, and is context dependent. Both Mandarin and Kurdish are minority languages in Canada, but Mandarin is more widely spoken, and in some regions, educational programs in this language are offered (Statistics Canada, http://www.stancan.ca; Edmonton Publish Schools, http://www.epsb.ca). Some languages are technically minority languages in a country as a whole, like Spanish in the United States, because of the proportional number of speakers countrywide, and lack of full institutional status. But in some regions of this country, like the city of Miami and surrounding districts, it could be construed as a majority language (Eilers, Oller, & Cobo-Lewis, 2002).