The organization of this book is based on the idea that human language has a small set of basic properties, each of which plays a role in the workings of language as an instrument for communication and thought. Each chapter in the book (after this one) introduces a new property. Chapter 2 discusses words and word meaning. Chapter 3 discusses phonological categories, the units that are combined to make word forms. Chapter 4 discusses phonological processes, the ways in which the units of word form interact with one another. Chapter 5 discusses compositionality, the principle that allows complex meanings to be expressed by combinations of words. Chapter 6 discusses how words are organized into larger units and how these allow us to refer to states and events in the world. Chapter 7 discusses how the grammars of languages divide the world into abstract conceptual categories. Chapter 8 discusses the productivity and flexibility of language and how grammar makes this possible. - Amira