A prefix is an affix which is placed before the stem of a word.
Some languages allow multiple prefixes before a stem , for example in English the word unenforceable consists of two prefixes, a root, and a suffix:
| un- | en- | force | -able |
| PREFIX- | PREFIX- | ROOT | -SUFFIX |
Some prefixes change depending on the root, for example in English in- becomes im- before certain roots:
insecure, incapable, inaccurate but immovable, impatient.
In some languages, hyphens are used to show how words are broken up into different morphemes.