Susan M. Gass is University Distinguished Professor of Second Language Studies at Michigan State University. She has served as president of the American Association of Applied Linguistics (AAAL) and the International Association of Applied Linguistics (AILA). Throughout her career, she has made groundbreaking contributions to advance the study of SLA, and remains one of the leading figures in the field. She is the winner of numerous local, national, and international awards.

Jennifer Behney is Associate Professor of Italian and Applied Linguistics in the Department of World Languages and Cultures at Youngstown State University. Her work has appeared in Foreign Language Annals, Studies in Second Language Acquisition, and several book chapters, and she was co-editor of a volume on salience in SLA. She was the recipient of the 2019 Ed Allen Award for Outstanding College World Language Instructor.

Luke Plonsky (PhD, Michigan State University) is Associate Professor of Applied Linguistics at Northern Arizona University, where he teaches courses in SLA and research methods. His work in these areas can be found in over seventy articles, book chapters, and books. Luke is Senior Associate Editor of Studies in Second Language Acquisition, Managing Editor of Foreign Language Annals, Co-Editor of de Gruyter Mouton's Series on Language Acquisition, and Co-Director of the IRIS Database (iris-database.org). In addition to prior appointments at Georgetown University and University College London, Luke has taught in Japan, the Netherlands, Poland, Puerto Rico, and Spain.

Now in a fifth edition, this bestselling introductory textbook remains the cornerstone volume for the study of second language acquisition (SLA). Its chapters have been fully updated, and reorganized where appropriate, to provide a comprehensive yet accessible overview of the field and its related disciplines.

Part One: Preliminaries

Chapter One: Introduction

1.1 THE STUDY OF SECOND LANGUAGE ACQUISITION

1.2 DEFINITIONS

1.3 THE NATURE OF LANGUAGE

1.3.1 Semantics

1.3.2 Pragmatics

1.3.3 Syntax

1.3.4 Morphology and the Lexicon

1.3.5 Sound Systems

1.4 THE NATURE OF NONNATIVE SPEAKER KNOWLEDGE

1.5 CONCLUSION

Chapter Two: Where Do Data Come From?

2.1 DATA TYPES

2.2 LEARNER CORPORA

2.3 DATA ELICITATION

2.3.1 Measuring General Proficiency

2.3.2 Measuring Nonlinguistic Information

2.3.3 Verbal Report Data

2.3.3.1 Think-Alouds

2.3.3.2 Stimulated Recall

2.3.3.3 Post-Production Interviews

2.3.4 Narrative Inquiry

2.3.5 Language-Elicitation Measures

2.3.5.1 Elicited Imitation

2.3.5.2 Judgments

2.3.5.3 Language Games

2.3.5.4 Discourse Completion

2.3.6 PROCESSING DATA

2.3.6.1 Reaction Time

2.3.6.2 Self-paced Reading

2.3.6.3 Eye-Tracking

2.3.6.4 Neurolinguistic Data

2.4 REPLICATION

2.5 META-ANALYSES

2.6 ISSUES IN DATA ANALYSIS

2.7 WHAT IS ACQUISITION?

2.8 CONCLUSION

Part Two: Historical Underpinnings of SLA Research

Chapter Three: The Role of the Native Language - A Historical Overview

3.1 INTRODUCTION

3.2 BEHAVIORISM

3.2.1 Linguistic Background

3.2.2 Psychological Background

3.3 CONTRASTIVE ANALYSIS HYPOTHESIS

3.4 ERROR ANALYSIS

3.5 CONCLUSION

Chapter Four: The Transition Period

4.1 INTRODUCTION

4.2 FIRST LANGUAGE ACQUISITION

4.2.1 Words

4.2.2 Sounds and Pronunciation

4.2.3 Syntax

4.2.4 Morphology

4.3 CHILD L2 ACQUISITION

4.4 CHILD L2 MORPHEME ORDER STUDIES

4.5 ADULT L2 MORPHEME ORDER STUDIES

4.6 THE MONITOR MODEL

4.6.1 The Acquisition-Learning Hypothesis

4.6.2 The Natural Order Hypothesis

4.6.3 The Monitor Hypothesis

4.6.4 The Input Hypothesis

4.6.5 The Affective Filter Hypothesis

4.6.6 Limitations

4.7 CONCLUSION

Chapter Five: Alternative Approaches to the Role of Previously Known Languages

5.1 REVISED PERSPECTIVES ON THE ROLE OF THE NATIVE LANGUAGE

5.1.1 Avoidance

5.1.2 Differential Learning Rates

5.1.3 Different Paths

5.1.4 Overproduction

5.1.5 Predictability/Selectivity

5.1.6 L1 Influences in L2 Processing

5.1.7 Morpheme Order

5.2 CONCLUSION

Part Three: A Focus on Form - Language Universals

Chapter Six: Formal Approaches to SLA

6.1 INTRODUCTION

6.2 UNIVERSAL GRAMMAR

6.2.1 Initial State

6.2.1.1 Fundamental Difference Hypothesis

6.2.1.2 Access to UG Hypothesis

6.2.2 UG Principles

6.2.3 UG Parameters

6.2.4 Minimalist Program

6.2.5 Falsification

6.3 TRANSFER: THE GENERATIVE/UG PERSPECTIVE

6.3.1 Levels of Representation

6.3.2 Clustering

6.3.3 Learnability

6.4 THE FUNDAMENTAL DIFFERENCE HYPOTHESIS REVISED

6.5 SEMANTICS AND THE SYNTAX-SEMANTICS INTERFACE HYPOTHESIS

6.5.1 Semantics

6.5.2 Syntax and Semantics: The Interface Hypothesis

6.6 PHONOLOGY

6.6.1 Markedness Differential Hypothesis

6.6.2 Similarity/Dissimilarity: Speech Learning Model

6.6.3 Optimality Theory

6.6.4 Ontogeny Phylogeny Model

6.7 CONCLUSION

Chapter Seven: Typological Approaches

7.1 TYPOLOGICAL UNIVERSALS

7.1.1 Test Case I: The Accessibility Hierarchy

7.1.2 Test Case II: The Acquisition of Questions

7.1.3 Test Case III: Voiced/Voiceless Consonants

7.2 FALSIFIABILITY

7.3 TYPOLOGICAL UNIVERSALS: CONCLUSION

7.4 TYPOLOGICAL PRIMACY MODEL

7.5 THE ROLE OF THE L1: THREE APPROACHES

7.6 CONCLUSION: GENERAL COMMENTS ABOUT UNIVERSALS

Part Four: A Focus on Meaning

Chapter Eight: Meaning-based Approaches

8.1 INTRODUCTION

8.2 FUNCTIONAL APPROACHES

8.2.1 The Relationship between Form and Function: Form-to-Function

8.2.2 Concept-oriented Approach

8.3 TENSE AND ASPECT: THE ASPECT HYPOTHESIS

8.4 THE DISCOURSE HYPOTHESIS

8.5 CONCLUSION

Chapter Nine: The Lexicon

9.1 THE SIGNIFICANCE OF THE LEXICON

9.2 LEXICAL KNOWLEDGE: WHAT DOES IT MEAN TO KNOW A WORD?

9.2.1 Production and Reception

9.2.2 Knowledge and Control

9.2.3 Breadth and Depth

9.2.4 Subcategorization

9.2.5 Word Associations and Networks

9.2.6 Word Formation

9.2.7 Formulaic Language, Collocations, and Chunking

9.2.7.1 Use of Multiword Units

9.2.7.2 Learning of Multiword Units

9.2.7.3 Processing of Multiword Units

9.3 INFLUENCES ON L2 VOCABULARY AND DEVELOPMENT

9.3.1 The Role of the L1

9.3.2 Incidental Vocabulary Learning

9.3.2.1 Input Type

9.3.2.2 What Helps Learning?

9.3.3 Depth of Processing

9.3.4 Incremental Vocabulary Learning

9.4 USING LEXICAL SKILLS

9.4.1 Production

9.4.2 Perception

9.5 CONCLUSION

Part Five: Cognitive and Processing Approaches to SLA

Chapter Ten: Psycholinguistic Approaches to Learning

10.1 INTRODUCTION

10.2 MODELS OF LANGUAGE PRODUCTION

10.3 PROCESSABILITY THEORY

10.4 PROCESSING OF INPUT

10.4.1 Input Processing

10.4.2 Processing Determinism

10.4.3 Autonomous Induction Theory

10.4.4 Shallow Structure Hypothesis

10.5 EMERGENTIST MODELS

10.5.1 Competition Model

10.5.2 Frequency-based Accounts

10.6 COMPLEX DYNAMIC SYSTEMS

10.7 SKILL ACQUISITION THEORY

10.8 CONCLUSION

Chapter Eleven: Psycholinguistic Constructs and Knowledge Types

11.1 INTRODUCTION

11.2 INFORMATION PROCESSING

11.2.1 Automaticity

11.2.2 Restructuring

11.2.3 U-shaped Learning

11.2.4 Attention

11.2.5 Working Memory

11.2.6. Salience

11.2.7 Priming

11.3 KNOWLEDGE TYPES

11.3.1 Acquisition/Learning

11.3.2 Declarative/Procedural

11.3.3 Implicit/Explicit

11.3.4 Representation/Control

11.4 INTERFACE OF KNOWLEDGE TYPES

11.4.1 No Interface

11.4.2 Weak Interface

11.4.3 Strong Interface

11.5 CONCLUSION

Part Six: The Social Environment of Learning

Chapter Twelve: Interlanguage in Context

12.1 INTRODUCTION

12.2 SOCIOCULTURAL APPROACHES

12.2.1 Mediation

12.2.2 Internalization

12.2.3 Zone of Proximal Development

12.2.4 Private Speech

12.2.5 Learning in a Sociocultural Framework

12.2.6 Gesture and SLA

12.3 SOCIOLINGUISTIC VARIATION

12.4 SYSTEMATIC VARIATION

12.4.1 Linguistic Context

12.4.2 Social Context Relating to the Native Language

12.4.3 Social Context Relating to Interlocutor, Task Type, and Conversational Topic

12.4.4 Sociolinguistic Norms

12.5 CONVERSATION ANALYSIS

12.6 COMMUNICATION STRATEGIES

12.7 L2 PRAGMATICS

12.8 CONCLUSION: SLA AND OTHER DISCIPLINES

Chapter Thirteen: Input, Interaction, and Output

13.1 INTRODUCTION

13.2 INPUT

13.3 COMPREHENSION

13.4 INTERACTION

13.5 OUTPUT

13.5.1 Hypothesis Testing

13.5.2 Automaticity

13.5.3 Meaning-based to Grammar-Based Processing

13.6. Feedback

13.6.1 Negotiation

13.6.2 Corrective Feedback

13.6.2.1 Recasts

13.6.2.2 Elicitation

13.6.2.3 Metalinguistic Feedback

13.7 THE ROLE OF INPUT AND INTERACTION IN LANGUAGE LEARNING

13.7.1 The Functions of Input and Interaction

13.7.2 Effectiveness of Feedback

13.7.2.1 Attention

13.7.2.2 Contrast Theory

13.7.2.3 Metalinguistic Awareness

13.7.3 Who Benefits From Interaction: When and Why?

13.8 LIMITATIONS OF INPUT

13.9 CONCLUSION

Chapter Fourteen: Contexts of Language Learning - Classrooms, Study Abroad, and Technology

14.1 INTRODUCTION

14.2 CLASSROOM-BASED INSTRUCTION

14.2.1 Classroom Language

14.2.2 Teachability/Learnability

14.2.3 Focus on Form and Task-based Language Teaching

14.2.3.1 Timing

14.2.3.2 Forms to Focus On

14.2.3.3 Task Design

14.2.3.4 Input Manipulation and Input Enhancement

14.3 COMPLEXITY, ACCURACY, FLUENCY, AND PLANNING

14.4 PROCESSING INSTRUCTION

14.5 UNIQUENESS OF INSTRUCTION

14.6 EFFECTIVENESS OF INSTRUCTION

14.7 SLA AND CLASSROOM PRACTICES

14.8 ADDITIONAL CONTEXTS

14.8.1 Study Abroad

14.8.2 Technology-enhanced Language Learning

14.9 CONCLUSION

Part Seven: The Individual Language Learner

Chapter Fifteen: Learner-internal Influences

15.1 INTRODUCTION

15.2 THE INFLUENCE OF PSYCHOLOGY IN SLA

15.3 METHODOLOGICAL CONSIDERATIONS

15.4 AGE DIFFERENCES

15.5 APTITUDE

15.6 MOTIVATION

15.6.1 Motivation as a Function of Time and Success

15.6.2 Changes over Time

15.6.3 The L2 Motivational Self System

15.6.4 Influence of Success on Motivation and Demotivation

15.7 AFFECT

15.7.1 Anxiety

15.7.2 Other Emotional Variables

15.8 PERSONALITY

15.8.1 Extroversion and Introversion

15.8.2 Grit

15.9 LEARNING STRATEGIES

15.10 CONCLUSION

Chapter Sixteen: Related Disciplines - A Focus on the Multilingual and Multimodal Learner

16.1 INTRODUCTION

16.2 BILINGUAL ACQUISITION

16.3 THIRD LANGUAGE ACQUISITION/MULTILINGUALISM

16.4 HERITAGE LANGUAGE ACQUISITION

16.5 SLA BY THE DEAF/HARD OF HEARING

16.6 CONCLUSION

Part Eight: Conclusion

Chapter Seventeen: An Integrated View of Second Language Acquisition

17.1 AN INTEGRATION OF SUB-AREAS

17.1.1 Apperceived Input

17.1.2 Comprehended Input

17.1.3 Intake

17.1.4 Integration

17.1.5 Output

17.2 CONCLUSION