Lexical Categories: The Organization Of The Syntax Of English

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Lexical Categories

A lexical category can be defined as a group of words which can substitute for one another in a similar position in a sentence or construction without affecting the grammaticality of the sentence in which they occur. For example, nouns can occur in subject, object, or complement positions in a sentence of English. Therefore, all nouns belong to a category. In the same vein, verbs, adjectives, etc., are grouped into categories based on their regular positions in sentences.

Lexical categories are determined in a string of words as in example (1) below:

1. The book is on the table

Det N V P Det N

We thus see that lexical categories are represented as Det (Determiner), N (Noun), V (Verb), P (Preposition), and so on. We can also distinguish the following categories:

Adv (Adverb) – quickly, soon, …

Adj (Adjective) – good, white, …

Conj (Conjunction) – and, but, or, …

Aux (Auxiliary Verb) – be, have, …

Mod (Modal) – can, shall, may, …

Q (Quantifier) – all, every, some, …

As can be seen from the above, quantifiers are usually distinguished from determiners.

Every lexical category often projects its own phrasal category. For example, N projects NP, V projects VP, and P projects PP. Thus, it is the lexical category that determines the phrasal category as in (2) below:

2. XP

X

In (2), the lexical category X (where X represents a category variable) projects a phrasal category XP, and X is the lexical head of XP.

The head is very important in X-bar theory. The primacy of the head starts from the D-structure. Each head is projected from the D-structure in what is called the Projection Principle. Put informally, the principle states that each head must be represented at all levels of analysis. These levels are the D-structure, S-structure, and logical form (a term approximating to meanings). Given the importance of the head, it has some unique features. First, it is the only obligatory category in a phrase, and other words (its satellites) modify it. Second, it determines the structure of the words or phrases adjacent to it. For instance, a noun head in a noun phrase may not be premodified directly by an adverb. Only determiners, numerals, adjectives, etc., can premodify the noun head. Also, adjective heads do not allow premodification by nouns. This is due to the lexical properties of each head in a phrase.

Chomsky (1970, 1986) introduced binary distinctive features [±N, ±V, etc.) to classify the four major lexical categories:

[+N, -V] = Noun

[-N, +V] = Verb

[+N, +V] = Adjective

[-N, -V] = Preposition

The binary features are meant to describe each major lexical category distinctly. Thus, [+N, -V] describes a word which has the property of nouns but not of verbs (e.g., king), while [+N, +V] describes words that have properties of both nouns and verbs. For instance, poor can be used as a noun (e.g., the poor) and as an adjective (e.g., the poor man).

Lexical categories can occupy any syntactic position in a sentence. The relationship between these syntactic categories can be graphically represented in a labeled tree diagram, where the category labels constitute nodes of the tree, and lines between nodes indicate branches. Consider the constituent structure of PP in a tree diagram in (3):

3. PP

P NP

Det N

on the table

In the above, P, NP, Det, and N are constituents of PP. The relationship between P and PP is quite different from the relationship between N and PP. P is an immediate constituent of PP, whereas N is not. Immediate constituent can be defined as follows:

4. A category B is an immediate constituent of a category C if and only if

(a) B is a constituent of C, and

(b) B is not a constituent of any constituent of C.

In terms of a tree diagram, B is an immediate constituent of C if they are connected by a single line; in that case, C is immediately above B in the diagram. Hence, we can say that PP is a phrasal category that contains a P, a lexical category, and an immediate constituent.

In conclusion, a lexical category is an immediate constituent. The lexical category is the terminal string that terminates the phrase structure derivation.

CONCLUSION

In this unit, we saw that words are grouped into classes or categories according to their regular positions in a sentence or construction. This grouping is referred to as a lexical category. The lexical categories are heads of the phrases they project, and they constitute the terminal strings of a derivation.