Acknowledgements Introduction PART ONE - BACKGROUND Introduction 1. Second language acquisition research: an overview PART TWO - THE DESCRIPTION OF LEARNER LANGUAGE Introduction 2. Learner errors and error analysis 3. Developmental patterns: order and sequence in second language acquisition 4. Variability in learner language 5. Pragmatic aspects of learner language PART THREE - EXPLAINING SECOND LANGUAGE ACQUISITION: EXTERNAL FACTORS Introduction 6. Social factors and second language acquisition 7. Input and interaction and second language acquisition PART FOUR - EXPLAINING SECOND LANGUAGE ACQUISITION: INTERNAL FACTORS Introduction 8. Language transfer 9. Cognitive accounts of second language acquisition 10. Linguistic universals and second language acquisition PART FIVE - EXPLAINING INDIVIDUAL DIFFERENCES IN SECOND LANGUAGE ACQUISITION Introduction 11. Individual learner differences 12. Learning strategies PART SIX - CLASSROOM SECOND LANGUAGE ACQUISITION Introduction 13. Classroom interaction and second language acquisition 14. Formal instruction and second language acquisition PART SEVEN - CONCLUSION Introduction 15. Data, theory, and applications in second language acquisition research Glossary Bibliography Author index Subject index