Strategies of teaching knowledge in English-medium instruction lectures: A Legitimation Code Theory perspective

English-medium instruction (EMI) has emerged as a predominant educational approach for disseminating disciplinary knowledge in tertiary institutions. Existing research has extensively examined the pedagogical dimensions of EMI pedagogy, such as its structures, instructor practices, and student experiences, with less attention being paid to the knowledge expressions and their pedagogical implications. The present study explores the construction of disciplinary knowledge and the strategies used in its dissemination in a live EMI lecture. Adopting a case study method, this study collected data through non-participant naturalistic observation, with subsequent analysis undertaken with reference to Semantics in Legitimation Code Theory (LCT). Findings reveal that disciplinary knowledge was cumulatively built through progressively condensing multiple meanings and rhetorically unpacked via strategies of comparing and expositing. These recurrent patterns engendered two pedagogical strategies: interactive and separate strategies. These findings could provide valuable insights for improving teaching quality and advancing interdisciplinary dialogue between EMI and LCT research. • Knowledge is not effectively taught in English-medium instruction lectures. • Patterns of building and unpacking knowledge improve teaching quality. • Knowledge could be cumulatively built by individual words and their combinations. • Knowledge could be unpacked by defining or expositing it with everyday language. • These structures highlight interactive and separate strategies of teaching knowledge.