It has previously been suggested that there is a need for a more language focused science instruction, especially in linguistically diverse classrooms, where many students are second language learners. But it has also been suggested that teachers may feel uncertainty about how to teach in ways that promote learning of both subject matter and language. Previous studies have revealed "how" the language of science, especially the written language of science, is used to create a certain meaning. Research on interventions shows how this knowledge, through a functional metalanguage, can be used successfully. However, few studies explore how teachers in science instruction themselves integrate a language focus in their linguistically diverse classrooms. This ethnographic case study investigates how a teacher, through her planned metalanguage activities, integrated language in her physics classrooms in Year 5. The results reveal that (1) the activities focused on the students' literacy development; (2) the activities sometimes had "an integrated language and subject focus" and sometimes "an isolated language focus"; and (3) the students put a great deal of effort into understanding how they were to perform the various "framed" activities. The study has implications for how a language focus can be integrated in subject teaching.