Examples (1) and (2) of chapter 4 showed that good Phrase Structure rules can produce bad sentences. We hinted that the solution to this problem was to be found in the lexicon, the speaker's mental dictionary, where information about the unique properties of individual words is stored. This topic is the focus of the present chapter. In particular, we will be interested in the lexical properties of the verb and the ways in which these properties determine the structure of the clause as a whole.

Lexical entries

Linguists use the term lexicon to refer to the collection of all the words (or meaningful elements) in the language; we often think of it as the speaker's “mental dictionary.” Each individual word is referred to as a lexical item. For each lexical item, the lexicon must specify how it is pronounced, what it means, and how it patterns in the grammar.

All of the phonological, semantic, and grammatical information which is specific to a particular word is included in its lexical entry. This lexical entry is somewhat analogous to an entry in a normal printed dictionary, which provides information about pronunciation, meaning, and part of speech. However, the grammatical information contained in a lexical entry may go far beyond the word's part of speech (syntactic category). For example, we noted in chapter 4 that one of the diagnostic features for nouns in English is that they can be inflected for number.