This article explores, from within the social constructivist paradigm and drawing on data from twenty-one semi-structured interviews with international postgraduate university students approaching the end of a one-year full-time taught Masters degree in the UK, the range of language development brokers that have had an impact on these students' trajectory from language learner to language user. Students from a range of first language backgrounds contributed insights about key people, outside formal language teaching contexts, who supported and resourced their language development. While existing research has tended to focus on formal language instruction settings, this article puts forward insights to inform the fine tuning of language development provision in English-medium instruction (EMI) contexts outside traditional language classrooms, and to contribute to EMI students' academic and professional success.