I literally don't understand sickth. It's six with a th on the end. Do sickth sayers leave out random letters in "fourth" or "seventh" or "tenth"? Are there people walking around saying "fouth" and "seveth" and "teth"?
Side note, people who say "fith" instead of "fiFth" make me twitch as well.
(This post took fecking ages to write because autocorrect kept trying to fix things..... I feel you, Autocorrect, I feel you)
ETA for actual genuine spelling errors 😒