This chapter discusses the necessary components of second language acquisition, that is, input, interaction, and output. While all language learning theories support the importance of input (written and spoken), they diverge in ways which input is connected to second language acquisition. The chapter then examines some of the second language acquisition theories, such as the interaction hypothesis, the noticing hypothesis, the cognitive-interactionist approach, the output hypothesis, and sociocultural theory, all of which explains how interaction leads to second language acquisition. The chapter moves onto specific pedagogical frameworks that support interaction, including communicative language teaching and task-based language teaching. Finally, the chapter delves into the role that output plays by discussing its functions for second language acquisition.

Drawing from classroom examples of ‘focus on form’, this chapter demonstrates how ‘form’ covers more than just grammar. Referring to second language acquisition research, it explores why a focus on form may be particularly important in the foreign language learning context and why the adolescent learner may be particularly able to benefit from opportunities to focus on features of language. The chapter presents a wide range of options of opportunities to focus on form, including an emphasis on the importance of giving explanations and on the potential for learners to learn from the feedback they get when using the language to communicate. The chapter draws on examples from a range of language classrooms and, also includes examples of the types of planned exercises teachers use to draw learner attention to form.

The chapter outlines the interactionist approach to corrective feedback in second language (L2) acquisition. Input-providing and output-prompting feedback types are addressed, including their potential role in facilitating L2 development. Historical and contemporary interactionist research is overviewed, and suggestions are made for future work in this area. The chapter closes with pedagogical recommendations for the use of corrective feedback in L2 classrooms.

This chapter considers the role corrective feedback plays in second language vocabulary acquisition. The first half of the chapter considers the effects of oral corrective feedback. We first provide a classification of oral corrective feedback, and then discuss findings from existing descriptive and experimental studies, followed by pedagogical implications of the findings. Past studies have suggested that vocabulary tends to benefit more from oral corrective feedback than grammar or morphosyntax, possibly due to the high degree of noticeability and less complex abstract nature of vocabulary. The latter half of the chapter discusses the effects of written corrective feedback. After providing a classification of written corrective feedback, we present two major research frameworks: feedback-for-accuracy and feedback-for-acquisition. The chapter then presents results of experimental studies, followed by pedagogical implications of the findings. Existing studies have suggested that written corrective feedback may lead to more appropriate use of vocabulary in subsequent revisions; however, it is not yet clear whether these positive effects can be carried over to a new piece of writing. The chapter concludes with suggestions for further research and calls for more research comparing the effects of different types of corrective feedback, both oral and written, on vocabulary learning.