The skill, awareness, and perhaps the competence, of language learners to engage in specific interactional behaviors are currently encapsulated in the term Interactional Competence (IC). While IC-oriented teaching materials propose learning targets beyond vocabulary and sentence level grammar, their action-oriented view of what language is and how language works contrasts with basic notions of language and proficiency currently reflected in transnational curriculum guidelines and assessment protocols. This paper illustrates how IC-oriented teaching materials can be conceptualized for, and used in, the second language classroom and argues that their use encourages a rethinking of the notions of language and proficiency for second language teaching. [For the complete volume, "Classroom-Based Conversation Analytic Research: Theoretical and Applied Perspectives on Pedagogy. Educational Linguistics. Volume 46," see ED660574.]