In the word quickly -ly is a?
Ly is added at the end of a word so that makes it a suffix.
Words that end in 'ly' are adverbs, or verb modifiers. Often, 'ly'
can be added on to the adjective form of a word. For example,
"quick" is an adjective, but add 'ly' and you get "quickly" which
tells you how something was done. "I read the book quickly." How
did you read the book? Quickly.