The chapters in this section form the foundations of the book in the sense that they deal with aspects of practice that should hold true for all learners in all contexts. Part II will deal with variations due to institutional contexts and Part III with individual differences.

Input and output have been discussed many times in the applied linguistics and second language acquisition literature, but only in recent years has attention been focused on what exactly the role of input and output practice is. For centuries, language teaching, whether grammar-translation, audiolingual, cognitive-code, or communicative, had put emphasis on output activities but with very divergent underlying philosophies. Krashen's monitor model and Krashen and Terrell's natural approach were radical breaks with that tradition in the sense that they saw only a minimal role for output practice, seeing output as largely unproblematic, provided the relevant competence had been acquired. Acquisition of competence, in turn, was viewed as a matter of enough meaning-focused processing of the right (“comprehensible”) kind of input, not a matter of systematic practice in the sense of this book (i.e., specific activities in the second language, engaged in systematically, deliberately, with the goal of developing knowledge of and skills in the second language; see Chapter 1), even though some of the activities advocated by Krashen and Terrell as a means of providing meaningful and comprehensible input would certainly qualify as practice from our point of view.