How do people learn language? This volume concerns human learning in general and the ability to acquire second, foreign and native languages in particular. It is generally agreed that there are three quite different types of human learning: implicit learning (a non-conscious, automatic abstraction of structure); explicit learning (where, as in problem solving, the learner searches for information and builds and tests hypotheses), and learning as a result of explicit instruction. But how do these processes result in language acquisition? The motivation for this book is that no one discipline can answer this question.