The status of adjectives

What is the status of adjectives in the present grammatical typology? The notion of modifier is central to this taxonomy. Thus, the adjective is a noun modifier. In the expression ‘the blue sky’, ‘blue’ is a modifier of the noun ‘sky’. The definition of the adjective as a noun modifier is quite in line with the definition given for example by Merriam-Webster: ‘a word belonging to one of the major form classes in any of numerous languages and typically serving as a modifier of a noun to denote a quality of the thing named, to indicate its quantity or extent, or to specify a thing as distinct from something else’.