Two major trends outline the university of the twenty-first century, innovative online instructional technologies and English-Medium Instruction (EMI). As regards the former, new technology-driven lecture formats have emerged, such as live online lectures. These lectures are characterised by the permanent spatial separation of learners and teacher, and real time instruction, which allows for immediate two-way communication through text-, audio-, and/or video-based systems (Martin, Ahlgrim-Delzell, & Budhrani, 2017). The second trend refers to the internationalisation of the university, as EMI is considered to be playing a key role in this process. Although EMI in non-English dominant contexts has spread worldwide, literature on EMI classroom discourse is still at an infant stage (Macaro, Curle, Pun, An, & Dearden, 2018) compared to, for example, the copious amount of research on teachers’ and learners’ perceptions and/or attitudes towards EMI (Aguilar & Rodríguez, 2012). Therefore, studies reflecting the dynamics of classroom discourse where English is used as a lingua franca (Björkman, 2013; Mauranen, 2012) are needed to disclose good practices for effective teaching in EMI programmes. Learner interaction with faculty and peers is central in any educational context, the more the learners are engaged in the construction and development of their learning, the more they learn (Carini, Kuh, & Klein, 2006). Hence, teachers have the responsibility to promote engagement through interaction in class; however, classroom interaction can be a challenge in this “new” lecturing format, due to the constraints of the virtual context where the communicative act takes place. Videoconferencing technology systems are employed in live online lectures; nonetheless, in general, teacher and learners communicate through different channels during the lectures: visual-oral mainly for teachers (who are in front of the camera) and written for learners (through a chat). In this communicative situation the lack of eye contact can hinder interaction. Additionally, silence is seen as a component of interaction (Poyatos, 2002) and thus as part of communication, and it can be deafening in live online lectures when learners do not respond to the teacher’s initiation move of an interaction exchange. The present study aims at exploring the influence in interaction of teaching through English as a lingua franca in an EMI virtual context. We were particularly concerned about how teacher’s silence was integrated and how learners’ stillness was managed during the interaction. With this purpose, we conducted a contrastive study of the episodes of interactions that took place in two live online lectures given by the same teacher, one in Spanish (L1) and the other in English, in two parallel online international master’s programmes. We focused on teacher’s eloquent silence (Ephratt, 2008), that is, the silence chosen by the teacher for significant verbal communication, and on learners’ stillness, which refers to learners’ absence of “talk”. We adopted a multimodal discourse analysis perspective to identify the different actions that took place during teacher’s silence and how these were expressed through multimodal ensembles of embodied and disembodied semiotic resources, as well as how the teacher promoted learners’ participation to avoid stillness. As the analysis revealed, some differences were observed in the two lectures, mainly as regards how engagement was fostered and how learning was scaffolded in the EMI lecture through the chat.