Australian students from disadvantaged contexts who speak English as a second language (ESL) are at risk of being developmentally vulnerable when compared to their peers (Gonski et al., 2011). This article presents selected findings from a large-scale longitudinal study designed specifically for young students in disadvantaged contexts. It reports the positive students' gains, and the challenges teachers faced while engaging and supporting students in developing their understanding of mathematics. Data were collected from Early Years students (Foundation to Year 2) across three schools with large identified ESL cohorts (N = 379). Additionally, data were also collected from the participating students' teachers (N = 35). The students were tested twice yearly, while the teachers were interviewed three times during the year(s) they participated in the project. The improvements in the students' pre- and post-test scores were statistically and educationally significant. The teachers identified two main challenges as they implemented a program called Representations, Oral Language and Engagement in Mathematics (RoleM). First, relates to language and communication difficulties when teaching students whose first language was not Standard Australian English, and second, the teachers had to rethink their pedagogical practices after participating in RoleM professional learning. The results of this study add to the literature with regard to the pedagogical approaches used to teach mathematics to ESL students. In particular by providing evidence that the concepts of representing and communicating mathematics are intertwined, and thus teaching mathematics as a linguistic experience should be avoided.