Dictate these words to the best speller you know and see how she does: larynx, minuscule, guttural, definitely, indispensable, supersede, sacrilegious, rhythm, judgment, bellwether, disinterred.
Check out this list of the top 100 misspelled words here.
Misspelled words on a business sign is a pet peeve of mine. I have called many businesses to report the wrong spelling. But when I saw "CONGRADULATE" on a high school sign; I almost had a heart attack. Yes, I called that school and the sign was changed within the hour.