Researchers and practitioners have long been interested in the role of learner agency in the emergence of learning opportunities. However, despite the growing number of studies, few of them have empirically been able to demonstrate how such moments can create learning opportunities. Based on 12 hours of videotaped data, this study describes the nature of learner initiatives in L2 oral communication classroom interaction and brings evidence for the emergence of situated cognition and learning. An in-depth conversation-analytic investigation of learner-initiated vocabulary explanation sequences reveals three types of sequences which include: (1) clarification request + vocabulary explanation and no claim/display of understanding format; (2) clarification request + vocabulary explanation and claim of understanding format, and (3) clarification request + vocabulary explanation and display of understanding format. The findings of this study contribute to the existing research on learner initiatives in instructed learning settings and language learning with a micro-analytic account of verbal and non-verbal aspects of situated cognition and learning emerging in L2 oral communication classroom interaction.