This paper presents findings from a study of teaching and learning strategies co-constructed by peers in a Spanish/English dual language first grade classroom. Grounded in sociocultural theory and developed using ethnographic approaches to data collection and analysis, the study analyses the children's mediation of their own and each other's language learning within and across languages, focusing on strategies that support learning. The strategies are analysed within the context of teaching/learning interactions in a Dual Language Programme with attention given to the children's ongoing negotiation of the linguistic roles of novice, expert, and dual language expert when working in mixed groups in the English and Spanish classrooms.