This book outlines Second Language Acquisition, the study of the way in which people learn a language other than their mother tongue. It is designed to make the essentials of this rapidly expanding area accessible to readers encountering it for the first time.

Introduction: Describing and explaining L2 acquisition --What is "second language acquisition"? -- What are the goals of SLA -- Two case studies -- Methodological issues -- Issues in the description of learner language -- Issues in the explanation of L2 acquisition -- The nature of learner language -- Errors and error analysis -- Developmental patterns -- Variability in learner language -- Summary -- Interlanguage -- Behaviourist learning theory -- A mentalist theory of language learning -- What is 'interlanguage'? -- A computational model of L2 acquisition -- Social aspects of interlanguage -- Interlanguage as a stylistic continuum -- The acculturation model of L2 acquisition -- Social identity and investment in L2 learning -- Discourse aspects of interlanguage -- Acquiring discourse rules -- The role of input and interaction in L2 acquisition -- The role of output in L2 acquisition -- Summary -- Psycholinguistic aspects of interlanguage -- L1 transfer -- The role of consciousness in L2 acquisition -- Processing operations -- Communication strategies -- Two types of computational model -- Linguistic aspects of interlanguage -- Typological universals: relative clauses -- Universal grammar -- Learnability -- The critical period hypothesis -- Access to UG -- Markedness -- Cognitive versus linguistic explanations -- Individual differences in L2 acquisition -- Language aptitude -- Motivation -- Learning strategies -- Instruction and L2 acquisition -- Form-focused instruction -- Learner-instruction matching -- Strategy training -- Summary -- Conclusion: multiple perspectives in SLA -- Readings -- Glossary.