Someone who's hoity-toity is pretentious and snooty. If you speak to someone in a hoity-toity accent, they are going to assume that you're a snob.
Your hoity-toity aunt might refuse to eat lunch in your favorite diner, insisting on someplace fancier, and a hoity-toity salesman might make you feel like you don't belong in an expensive department store with your old jeans and worn sneakers. The adjective hoity-toity started out meaning "riotous behavior" in the 1660s. By the late 1800s it had gained its modern meaning, probably out of similarity to the word "haughty."