This study examined the impact of video-based synchronous computer-mediated communication (SvCMC) on engagement in collaborative pre-task planning and L2 content used in task performance. One hundred twenty-eight Hong Kong learners of English were assigned to either a face-to-face (FTF) group (n = 64) or an SvCMC group (n = 64), where they completed planning for a monologic task. Based on Philp and Duchesne’s multidimensional model, planning was analyzed for cognitive (negotiation of meaning, semantically engaged talk), social (affiliative responses) and emotional engagement (enjoyment, anxiety), and task performance was coded for L2 content. Results showed that FTF mode led to significantly lower anxiety, more semantically engaged talk, and more affiliative responses, as well as conceptually richer task performances. Use of planned content was predicted by L2 proficiency and semantically engaged talk and negatively predicted by anxiety. Our findings contribute to an understanding of engagement in SvCMC and FTF modes and their impact on L2 learning.
