Affixes are groups of letters that are added to the beginning or end of a word to change the word's meaning. Prefixes are a type of affix added to the beginning of a word to alter its meaning or, in some cases, to create an entirely new word. For example, the word appear means “to become visible.” When students add the prefix dis- (which implies a negation of action) to the beginning of appear (base word), the meaning of disappear means “to cease to be visible.” Suffixes are affixes added to the ends of words to alter the meaning and create a new word. Suffixes can indicate the part of speech the word functions as. For example, the word hopeful consists of the suffix -ful (which means "full of") combined with the base word hope. Thus, the word hopeful means "full of hope." Recognizing affixes and understanding the specific changes they bring to a base word can help students to decode and process unfamiliar words as well as to manipulate and construct words of their own.