last changed in 2002
`Adjective' is a word-class, not a grammatical function. One of the two main uses of adjectives is `attributive', i.e. modifying a common noun (e.g. big book), but this does not mean that any word which modifies a common noun must be an adjective. For example, in big linguistics book, linguistics modifies book, and has the same grammatical function as big (namely, adjunct), but belongs to a different word-class: noun. This is easy to prove because linguistics may in turn be modified by an adjective, such as theoretical: thus in theoretical linguistics book, theoretical is an adjective modifying the noun linguistics, which in turn modifies book. Had linguistics been an adjective, it could not have taken another adjective as its modifier. For example, although nice big book is possible, with two adjectives, these both modify book; if we use them after BE only one is possible (*It is nice big), which shows that nice does not modify big (unlike, say, extremely in extremely big).
Most adjectives can be used in two ways, either attributively (as pre-adjuncts of common nouns) or predicatively (as sharer of a verb such as BE):
(1) That big book is heavy.
The structures concerned are shown here:
However, some (apparent) adjectives can only be used attributively (e.g. SOLE) and others only predicatively (e.g. ALONE):
(2) The sole/*alone survivor was Pat.
(3) Pat was alone/*sole.
It is not at all clear how best to handle these restrictions, and further research is certainly needed. Are SOLE and ALONE really adjectives? For the time being I assume that they are, but this may well be wrong.
This is an article from the Encyclopedia of Word Grammar and English grammar. If you refer to it, please give the url as "http://tinyurl.com/wg-encyc".