In the process of second language acquisition, the ability to interact effectively is critical. But what does it mean to be interactively competent? This book addresses this question by presenting research on the development of interactional competence among learners of Japanese as a second language. Qualitative data collected on learners studying abroad in Japan is evaluated to explain changes in their interactional competence and provides specific insights into the learning of Japanese. The situated analysis of multiple data sets generates meaningful interpretations of the development of interactional competence and the learner-specific factors that shape developmental trajectories. Moreover, the context of the research provides insights into the types of learning resources and experiences that study abroad provides to assist learners in their progress towards becoming a competent speaker in the target community.