This article seeks to develop the research agenda of multilingualism and multicompetence by bringing together three research fields and their related methodologies: bilingualism, third language acquisition and language learner strategies. After a brief introduction to each area, it describes a study to explore whether bilingual adolescent students learning French in two London schools outperform their monolingual peers in reading and listening comprehension. The significant difference in bilinguals students' listening comprehension test scores leads to in-depth analysis of qualitative data of three case study students in order to identify the differential features involved in the interaction of the languages. It appears that their greater use of oral/aural strategies is developed through the home environment; code-switching in the parental input fostering the development of the strategies. The article concludes with implications for pedagogy and for research.