The use of pairwork activities in language classrooms has been standard practice for many years now, but how does it actually help students advance in their learning? This book reports on an investigation into the learning processes of students in classrooms in a tertiary institution in Mexico. The study sought to go beyond the traditional foci of second language acquisition research, such as input and output and instead rely on a sociocultural framework to understand the link between language and thought. Students were recorded carrying out a variety of collaborative tasks and the data obtained was analysed to evaluate the quality of student interaction. Findings were shared with the students with the aim of promoting higher quality peer talk. The students were subsequently recorded doing further tasks. The results obtained indicate that peer talk is a powerful tool for the construction of knowledge.