Many adjectives have an adverbial form produced by adding an
-ly ending:
- quick → quickly
- accidental → accidentally
- local → locally
- recent → recently
- frequent → frequently
- happy → happily [replace -y with -ily]
Other adjectives have an irregular adverbial form:
- good → well [instead of goodly]
- early → early [adjective already ends in -ly]
Modern theories of grammar include adverbial forms of adjectives within the class of adjectives much as singular and plural nouns are included within the class of nouns. The reason is because they share most of the behaviour of the adjectives they are derived from. For example, gradable adjectives and adverbs both behave the same way in comparisons:
