The description of a language comprises three major components: phonology, grammar and lexicon. The phonology describes the sound system: consonants, vowels, stress, intonation, and so on. The two most basic units of grammar are the word and the sentence: one subcomponent of grammar, called morphology, deals with the form of words, while the other, called syntax, deals with the way words combine to form sentences. The lexicon – or dictionary, to use a more familiar term – lists the vocabulary items, mainly words and idioms (such as red herring, give up, and so on), specifying how they are pronounced, how they behave grammatically, and what they mean. In this book we will confine our attention to the grammar, with only occasional passing mention of phonological and lexical matters.

On another dimension we can distinguish between the study of linguistic form and the study of meaning: all three of the major components are concerned with aspects of both. The special term semantics is applied to the study of meaning, and we can accordingly distinguish phonological semantics (covering such matters as the meanings expressed by stress and intonation), grammatical semantics (dealing with the meanings associated with grammatical categories such as past tense, interrogative clause, and so on) and lexical semantics (the meanings of vocabulary items).

The relation between form and meaning in grammar is by no means straightforward. This is one of the issues we shall need to consider in this introductory chapter, where the aim is to explain briefly the model or framework of grammatical description that we shall be using in the book and the methodological approach adopted.