misspell vs. mispell

The word misspell is made up of the base word spell and the prefix “mis-” (meaning “badly or wrongly”). In careful diction, we pronounce each S separately: /mɪsˈspɛl/.

However, in more casual, informal speech, we tend to blend these two S sounds into one, sounding more like /mɪˈspɛl/. Because common pronunciation reduces the Ss down to a single sound, this tends to be reflected in writing with the misspelling mispell. Just remember that misspell contains both mis- and spell, so we need both Ss to write it correctly.