All languages use modulations in pitch to give shape to utterances. Pitch modulation functions in two ways: to encode lexical 'tone', that is, to signal boundaries between morphemes or words, and to encode 'intonation', that is, to give words and sentences a further meaning that isn't part of the meaning of the words themselves. Using examples from a wide variety of languages, this book explains why speakers vary their pitch, what these variations mean, and how they are integrated into our grammars.