L1 visual support in L2 academic listening: Implications for the strategic use of L1 on lecture slides in EMI contexts

Second language (L2) listening comprehension of lectures is a crucial but challenging aspect of content courses for L2 students in English as a medium of instruction (EMI) university contexts. Lecture slides are often used with the intent of enhancing comprehension of lecture content; however, the actual benefits for cognitive learning are not clear, especially for L2 students. Given that the use of the L1 is increasingly recognized as an effective pedagogical practice in situations where instructors and students share a common first language (L1), the current study considers the utility of L1 textual support on slides to support bottom-up and top-down processes in L2 lecture comprehension. In the current study, Japanese L1 learners of English ( n = 58) listened to two short academic lectures while viewing slides in one of three conditions: L2 text only, L2 text supplemented with L1 titles, and L2 text supplemented with L1 glosses of terminology. Immediate comprehension and delayed content retention were measured using true or false and integrated listening-to-summarize tests. Both L1 titles and L1 glosses of terminology demonstrated the potential to facilitate L2 lecture comprehension for learners, especially in delayed measures that tested retention of academic content.