The call for improving students' academic achievement in science education has increased in urgency in recent years. It has also increased in complexity in the face of the growing cultural and linguistic diversity of present-day classrooms following inter- and intra-state migration. Although "translanguaging" pedagogy, where languages of input and output are deliberately interchanged, remains a relatively young field of research, it has grown substantially in the past decade. The study presented in this article sought to explore the role language plays in the academic performance of multilingual students at a primary school in South Africa. Adopting an ethnographic research design, the author collected qualitative data through lesson observations video-recorded in a fifth-grade science class, supplemented with several interviews with the teacher. Data analysis involved a combination of both inductive and deductive methods, and the results affirm that translanguaging pedagogy is indispensable for effective learning in multilingual classrooms. The author's findings confirm insights from previous research that the ability and encouragement to use multiple languages in science class allows multilingual students to engage in a practice of generating and creating scientific explanations in their own voice, resulting in better academic performance.