Observed correlations between linguistic proficiency and school success, on the one hand, and existing differences in the academic success of immigrant students across countries, on the other hand, lead to the expectation that there are differences across countries in the early language development of immigrant children. The aim of the present study is therefore to pinpoint factors of success and failure with regard to the language development of bilingual immigrant children by looking across contexts. The contexts in this study are chosen on the basis of academic success: in Canada, immigrant students are rather successful, whereas in the Netherlands they perform below native levels. Immigrants in Canada and the Netherlands differ in socio-economic status, level of education, levels of integration in society, quality of schools immigrant children attend and clustering. These factors influence the quality and quantity of the language immigrant children are exposed to, which, in turn, will have an immediate effect on their linguistic proficiency. The method proposed in this study is innovative. Comparisons in terms of academic performance are routinely carried out between countries, but cross-context studies of early spoken language of immigrant children in contrastive environments, like Canada and the Netherlands, are non-existent. The outcome of this study is relevant for scientific purposes because it enables testing of input-driven approaches to language acquisition. From a societal perspective, the topic of this project is urgent. In the Netherlands, as in various other European countries, the proportion of immigrant children is increasing. Relatively high proportions of these children show delays in primary education. Insight in their language skills may be essential for understanding these delays.