English Toolkit

EXPLANATION In Latin, pre means before. A prefix, then, is a syllable that we attach to the beginning of a word to change its meaning. Knowing this, we should have no problem spelling a word with a prefix at the beginning of it. We simply take the original word and tack on the prefix. Thus dis+appear results in disappear.

Of course, if dis happens to come before a word starting with s, as in dis+similar, then the result is dissimilar. Thus, a double letter will result only when the prefix used ends with the same letter that the original word begins with. Other examples are immobile (im+mobile), illegible (il+legible), irregular (ir+regular).