Abstract: In this chapter we explore how teacher and student talk, as well as written text, helped to build meaning in a series of mathematics lessons in a remote Indigenous school. The topic of the lessons was telling the time using an analogue clock. In recording and analysing the lessons we identified three overarching purposes for language. First, the teachers used whole-class dialogue to establish shared understandings with their students about the purposes of telling the time and to orient the students to the relevant mathematical thinking. Second, they used language intentionally, in conjunction with symbolic and visual representations, to support the students in developing mathematical concepts. And third, they supported the students to use language, both spoken and written, as a mnemonic to help them remember how to carry out the mathematical processes involved in telling the time. Using writing as a mnemonic is a very basic function of literacy, but our research suggests it is nonetheless a valuable way of helping to make the learning more concrete, particularly when working with students who struggle with both literacy and numeracy. We suggest that, if used within a carefully devised teaching sequence, written text can be a critical resource that contributes to the overall meanings created through the interaction of linguistic, symbolic and visual systems in the classroom.