INTRODUCTION: Input Processing, Where Language Acquisition Begins

This is the introductory chapter to the volume, The Routledge Handbook of Second Language Acquisition and Input Processing. The handbook brings together different theoretical perspectives, empirical developments, methodological considerations, and instructional implications that highlight the centrality of input processing (IP) in second language acquisition in an effort to assess past and current research on IP and to engage the reader in a critical reflection about what lies ahead for future research, theory-building, and implications for practice. The chapter first provides a historical overview of IP research and defines key constructs to understanding IP before presenting critical issues that the volume addresses: (1) Why are models of IP considered internal theories? (2) How is IP conceptualized across different linguistic subsystems? (3) How does IP fit in different theories of language acquisition? (4) What is the relationship between input modality and IP? (5) What is the difference between IP and language processing? (6) How can IP theory and research inform L2 instruction? (7) What innovations in research methodology can take IP research to the next level? After presenting the key issues, the authors lay out the structure and features of the handbook and provide a brief description of each chapter in the volume.