One of the objectives of the South African science curriculum is to provide equal access to science for students from all backgrounds. However, this goal remains elusive as many students, particularly those from low socio-economic backgrounds, continue to perform poorly in science. One of the reasons for the persistent differential achievement in science is language. Yet the latest review of research in science education in South Africa conducted in 2009 identified only five papers focusing on language in science in the key journals reviewed. This paper presents a review of literature on language in science, with specific focus on research on the pedagogical functions of language in South African science classrooms in the past three decades. We extended the scope of the review by looking beyond the key journals considered in the 2009 review to include any other journal publications on language in science. Analysis of the research itself suggests that earlier studies focused on ways to resolve a perceived language crisis in English as a Second Language classrooms. There is a shift in focus with more recent research exploring the mobilisation of the linguistic resources of the classroom for learner conceptual engagement. We discuss these emerging trends.