Written by a team of leading experts working in different second language acquisition (SLA) specialisms, this fifth edition is a clear and concise introduction to the main theories of SLA from multiple perspectives, comprehensively updated to reflect the latest developments in SLA research. The book covers all the main theoretical perspectives currently active in SLA and sets each chapter within a broader framework. Chapters examine the claims and scope of each theory and how each views language, the learner, and the acquisition process, supplemented by summaries of key studies and data examples from a variety of languages. Chapters end with an evaluative summary of the theories discussed. Key features to this fifth edition include updated accounts of cognitive approaches to second language (L2) learning, the implications of advances in generative linguistics, and the “social turn” in L2 research; reworked chapters on functional, sociocultural, and sociolinguistic perspectives; an entirely new chapter on individual differences; and updated examples using recent studies. Second Language Learning Theories continues to be an essential resource for graduate students in second language acquisition.