Plural words, such as "forks" or "houses," involve the use of the suffix "-s." Suffixes can indicate different tenses, such as "walk" becoming "walked" with the addition of "-ed." Specific, everyday words using suffixes include "government," which is the word stem "govern" modified by the suffix "-ment," and "childish," which is the word stem "child" modified by the suffix "-ish."
A suffix is a letter, or series of letters, that changes the meaning of a word root when placed after it. Suffixes are either inflectional or derivational, meaning that they carry either grammatical or lexical information, respectively. Inflectional suffixes do not alter the class of a word; a verb modified by an inflectional suffix remains a verb. However, derivational suffixes can alter a word's word class, as seen when the noun "child" becomes the adjective "childish" when modified by the derivational suffix "-ish."
A word stem's inflectional paradigm is the list of all its different inflected forms, each modified by a different inflectional suffix. For example, the word "tall" may be modified to its comparative form of "taller" and its superlative form of "tallest." Irregularly, a paradigm may not continually make use of the same word stem. For example, the inflectional paradigm of the word "good" includes "better" and "best" rather than "gooder" and "goodest."