This book explores the complex relationship between theory, practice and research in online communication for language learning. Unlike no other publication currently available, it combines a discussion of the major concepts that underpin the field of computer-mediated communication for language learning with a mapping of the influences that research across various media has on practice and vice versa. The main concepts are drawn from multiple disciplines: Second Language Acquisition, sociocultural theory, multimodality, multiliteracies, online teaching/learning pedagogies. The book also presents a number of mainly qualitative research methodologies particularly suited to computer-mediated communication for language learning. It brings to the forefront a number of new phenomena that arise in online environments (such as affordances, mediation, collaborative learning, and identity)