The document explains prefixes and suffixes, which are letters added to the beginning or end of words that alter their meanings. It provides examples of various prefixes (e.g., ‘pre-’, ‘im-’, ‘bi-’) and suffixes (e.g., ‘-less’, ‘-ful’, ‘-ment’), along with root words from which new words are formed. Additionally, it includes exercises to identify root words and understand the function of prefixes and suffixes.