Many educators in immersion contexts support a policy of strict separation of languages in the classroom as the ideal model for second language acquisition and are reluctant to make connections between the dominant language, the target language and pupils' home languages. This can result in missed opportunities for drawing on pupils' entire linguistic repertoires to foster their learning The present study considers teachers' discourses surrounding the place and role of the dominant language (French), the target language (English) and home languages from the perspective of classroom teachers at one French primary school with a school-wide English immersion program participating in a collaborative research project. Since the program's inception in 2011, the one teacher/one language model has been adopted and approximately half the day is spent in each language. The analysis of the data comprising semi-structured interviews, filmed observations, stimulated video recall and focus group sessions revealed a shift in teachers' language awareness concerning the use of students' L1 as resources and their willingness to experiment with new pedagogies drawing on students' entire linguistic repertoires. The data highlighted challenges which emerged during the implementation of more flexible multilingual pedagogies as well as teachers' need for learning and long-term continued professional development.