Affixes like prefixes and suffixes can be added to word roots to form new words. Prefixes are added before the root while suffixes are added after. Common prefixes include "un", "non", "dis", "im", and "pre" and change the word's meaning to opposite, not, disorder, imperfect, or before. Suffixes like "-ing", "-ive", and "-ly" can turn nouns into adjectives, verbs into gerunds or nouns, verbs into adverbs, and more. Recognizing affixes is one of the most useful strategies for determining a word's meaning.