This volume brings together the current theoretical interest in reconceptualizing second and foreign language learning from a sociocultural perspective on language and learning, with practical concerns about second and foreign language pedagogy. It presents a set of studies whose focus is on the empirical description of particular practices constructed in classroom interaction that promote the learning of a second or foreign language. The authors examine in detail the processes by which the learning of additional languages is accomplished in the interaction of a variety of classrooms and in a variety of languages. Not only will the findings from the studies reported in this volume help to lay a foundation for the development of a more expansive, sociocultural model of second and foreign language learning, but on a more practical level they will help language educators in creating a set of principles for identifying and sustaining classroom interactional practices that foster additional language development.