International audienceWhile it is widely acknowledged that numerous factors can account for children's degree of bilingualism, the dynamic nature of the bilingual acquisition process makes it complex to analyse the roles played by different factors (Pearson 2007; De Houwer 2011; Unsworth 2014). As linguistic exposure changes over time, the roles of different factors evolve, resulting in language balance shifts. The data presented come from year one of a five-year longitudinal study which investigates the impact of linguistic exposure on a range of oral language performance variables. Participants are two groups of French-English bilingual children attending an international state school in France. Twenty children are aged 5-6 and 30 are age...