“It is a damn poor mind that can think of only one way to spell a word.” - Andrew Jackson
We're not going to judge. We've all got those few words that we need help with. Because Celtx is a browser-based software, you can use your browser's spellcheck option for all those sneaky little e's before i's and the like.
Depending on the browser you're using, you'll be able to adjust your dictionary regionally. You can always add words your dictionary doesn't recognize as well.