This article examines the nature of oral language and representations used by teachers as they instruct young Indigenous Australian students at the beginning of formal schooling during play-based activities in mathematics. In particular, the use of Standard Australian English (SAE), the mathematical register used, and the interplay with mathematical representations during classroom instruction are analysed based upon the teachers' selfreported practices. The data are drawn from structured telephone interviews with 40 teachers in 15 schools from rural and remote or multicultural settings in Queensland at the initial stage of a large, longitudinal study. The specific aim of the study was the identification of effective pedagogical practices that may assist young Australian students from diverse ethnic and cultural backgrounds to negotiate western mathematical understanding. The findings indicate that despite experience in these settings and focused professional learning sessions, the majority of these teachers report practices which reflect a strong emphasis on literacy acquisition rather than mathematical understanding. It is the contention of the researchers that the use of oral language with a rich selection of mathematical representations strongly supports mathematical understanding.