One of the most frequently misspelled English words only has three letters
The word that means "yes" is spelled "yea," not "yay."
"Yay" is what, for example, children say when they get ice cream. It wasn't even included in Webster's dictionary until fairly recently, since its earliest known usage was in 1963.
"Yea," on the other hand, is an archaic word (it appears 340 times in the King James Version of the Bible, from 1611) which survives today primarily in oral voting, as in, "Yea or nay?"
It's probably the most frequently misspelled English word percentage-wise, i.e., the ratio of the number of times people attempt to spell it to the number of times people get it wrong. I wouldn't be surprised if it's misspelled over 99% of the time on the internet alone.
Ironically, "yea" does get used frequently these days, but as a misspelling of "yeah."