To appear in Language Learning 2017 (Wiley-Blackwell) Video-based Interaction, Negotiation for Comprehensibility, and Second Language Speech Learning: A Longitudinal Study

The current study examined the impact of video-based conversational interaction on the longitudinal development (one academic semester) of second language (L2) production by collegelevel Japanese English-as-a-foreign-language learners. Students in the experimental group engaged in weekly, dyadic conversation exchanges with native speakers in the US via telecommunication tools, wherein the native speaking interlocutors were trained to provide interactional feedback in the form of recasts when the non-native speakers’ utterances hindered successful understanding (i.e., negotiation for comprehensibility). The students in the comparison group received regular foreign language instruction without any interaction with native speakers. The video-coded data showed that the experimental students incidentally worked on improving all linguistic domains of language, thanks to their native speaking interlocutors’ interactional feedback (recasts, negotiation) during the treatment. The pre-/post-test data led to significant gains in their comprehensibility, fluency and lexicogrammar, but not in the accentedness and pronunciation dimensions of their spontaneous production abilities. No significant improvement was found for the control group. The findings in turn support the acquisitional value of interaction, especially with regards to certain aspects of linguistic competence related to the early phase of L2 speech learning.