Prefixes, suffixes, and root words are components of words that can change their meaning. Prefixes are added to the beginning of root words, suffixes to the end, while root words are the basic part of a word. Common prefixes include "un-", "mis-", "re-", and "over-", and common suffixes are "-ness", "-able", "-ly", and "-ment". Understanding how prefixes and suffixes change word meanings can improve reading skills.