Adjectives and adverbs function to qualify other terms; adjectives qualify nouns and adverbs qualify verbs, adjectives, other adverbs and occasionally prepositions. Both classes are extendible. In each case there is a relatively small core general purpose lexicon which changes rarely and a larger domain specific lexicon which is constantly being revised and updated.

Interrogative and relative adjectives and adverbs are dealt with more fully in sections 12 below which deals with questions and relative clauses.