A prefix is a set of letters that comes before a word stem to form a new word, while a suffix does the same after a word stem. Examples of prefixes are "anti," "pre" and "mis." Some suffixes are "ion," "ism" and "ist."
In languages, a stem is the root word that takes the suffix or the prefix to form a new word. Often, prefixes change the meaning of a base adjective into its negative and the meaning of a base verb into its opposite. For example, for the adjective "lovable," the prefix "un" turns it into "unlovable."
When added to the end of a base word, suffixes may change the meaning of the word or act as inflections. The suffixes "s" and "es" are added to words to change them into their plural forms. In these cases, each suffix acts as an inflection, as it is added to the root word to create a new form of the word without changing its meaning. In other cases, suffixes are added to verbs to convert them into nouns. For example, a person can add the suffix "or" to the verb "sail" to create the noun "sailor."
Derivational suffixes are added to root words to change their meanings. For example, adding "ism" to the word "race" creates the new word "racism," which has a different meaning.