The present study was carried out in French immersion classrooms in an urban Quebec school board that is increasingly characterised by the heterogeneity of its Frenchdominant, English-dominant, and French/English bilingual student population. The study explored the extent to which a bilingual read-aloud project would (1) raise teachers' awareness of the bilingual resources of their students, (2) encourage students' crosslinguistic collaboration, and (3) promote teachers' cross-curricular and cross-linguistic collaboration. The participants were three English and three French teachers of three classes of six-to eight-year-old children. The French and English teachers of each class read aloud to their students from the same storybooks over four months, alternating the reading of one chapter in the French class and another in the English class. The data consist of (1) video recordings of the read-aloud sessions and discussion about the stories, (2) interviews and stimulated-recall sessions with the teachers, and (3) student focus-group interviews as well as a student questionnaire administered at the end of the project. Results are reported in terms of the enthusiasm of both students and teachers for the project, the opportunities it created for teachers and students to focus on both language and content, and the extent to which teachers collaborated to do so.Keywords: bilingual education; awareness-raising; collaboration; literacy practices; second language learning; cross-linguistic contrasts; immersion; reading aloud Introduction Over 40 years ago, an innovation in second language (L2) education began in the Englishmedium schools of St Lambert, a suburb of Montreal (see Lambert & Tucker, 1972). Anglophone children, a linguistic minority in the province of Quebec, had been receiving instruction in French, the majority language of the province, as a separate subject taught for a few hours a week. The new approach delivered a substantial portion of the academic school day through the medium of French, with the goal of improving the children's mastery of their L2. This subsequently triggered a rapid proliferation of such programmes across Canada, and immersion programmes have since been developed to teach a variety of languages in a wide range of contexts around the world (Johnson & Swain, 1997).This educational initiative became the prototypical model for immersion education. A key element of the model is a pedagogical approach that assumes homogeneous first language (L1) groups with similar L2 needs. However, as Swain and Lapkin (2005) have recently noted, (1) immersion students no longer necessarily share the same L1, and (2) the target language can no longer be accurately referred to as the L2 for many students, who increasingly represent culturally diverse and multilingual school populations. At the * Corresponding author. Email: roy.lyster@mcgill.ca There is a move towards dropping the prohibition against using students' L1 in the immersion classroom and instead developing practices more in line with findings ...