The use of English as a medium of instruction in universities to work with international and domestic students in Latvia is a current trend and deserves considerable attention. The present article shows the results of a study of the academic lectures in the institutional context. Theoretical findings include definitions of genre and discourse; a description of a lecture as a separate academic genre and of the peculiarities of spoken academic discourse, including lecturer's self-mention, expression of opinion (stance) and audience engagement. The article presents a study of the examples of extracts from the corpus of academic discourse and their descriptive analysis, as well as provides tables of lexico-grammatical features used to express stance and engagement.