English-medium instruction (EMI) courses in higher education have increased dramatically over the past decade and Japan is no exception. In the implementation of EMI courses, the role of English and the local language (Japanese) during content education is a subject of debate. The present study analyses EMI teacher talk by looking at aspects such as speech structure, and the role of language during content-education. Twelve undergraduate classes from four academic subjects in Economics, Ethics in Science, Project Planning, and Development Studies (three classes from each subject) were observed and recorded. Transcripts from these classes were analysed using Christie’s (1989) classroom discourse approach of curriculum genre, and Bernstein’s (1996) notion of horizontal and vertical discourses. Research findings revealed that there are similarities in EMI teachers’ classroom speech structure. However, the learning context has an effect on the role of English language which in turn influences content education.