The document discusses common prefixes in the English language and their meanings, including "re-", "un-", and "-ful". It provides examples of words containing these prefixes and how they modify the base word. Some key prefixes and their meanings mentioned are: - "re-" means to do again, as in redo, rewrite, or reread. - "un-" means not, as in unable, unsafe, or unkind. - "-ful" means full of, as in hopeful, playful, or joyful.