Language permeates our lives. For most people, on most days, language comprehension and language production are central activities, not only because of the time they occupy, but also because of the role they play in people's lives. For the most part we take our linguistic abilities for granted, though they may come to our attention when we encounter a word whose meaning we do not know or, more seriously, when we hear, or attempt to learn, a language with which we are not familiar. Indeed, people often show a remarkable lack of curiosity about the mental representations, mechanisms and processes that underlie their linguistic abilities. This chapter details some of the mental capacities on which the ability to understand language is based. ...