The swift growth in English medium instruction (EMI) in higher education has ended in the need for a bigger evidence base documenting EMI in practice spanning a series of settings. Inquiries of EMI centering on linguistic issues are starting to occur but there are little comparative studies considering multiple sites, levels and stakeholders. In reply to this, the inquiry reported here explored the roles of and conceptualisations of English and other languages in three EMI programmes in Thailand, Austria and the UK. A mixed-methods approach was assumed utilizing a student questionnaire (N = 121) and interviews (N = 12) with lecturers and students, backed by documentary assay and observations. Quantitative and qualitative analyses disclosed various roles of English and other languages, different levels of recognition of multilingualism, and a sophisticated set of conceptualisations of language by stakeholders. Especially, English as discipline-specific language use appeared as a crucial concept, straddling language and content learning and teaching, as well as problematising simplistic divides between language and content. Also, the intricate grasp of the various roles of languages by participants provides a counter to viewpoints of English in EMI as an unequivocal, rigid entity.