In this chapter I aim to analyse the different strategies adopted by a university instructor to introduce a plurilingual perspective in a business English course module that is part of the compulsory curriculum in a degree in Business Management and Administration at a university in Catalonia. I will examine how the instructor navigates the tension between what she considers a dominant perspective based on the idea that the most effective method to learn a foreign language is through immersion into the language and a new perspective according to which the learners’ knowledge of other languages can be used in order to speed up the learning of an additional language. The analysis will focus on the classroom discourse produced by the instructor in three class sessions corresponding to different stages of the academic term. First, I will look at the strategies that the instructor employed in order to legitimise her plurilingual approach in front of her students. Secondly, I will consider the instructor’s representations of language learning and use. Finally, I will focus on the instructor’s enactment of her plurilingual perspective through the interaction with her students.