Two decades ago I used to work long distance directory assistance in the United States. They trained us specifically for the city "Worcester" so we wouldn't be hopelessly confused when folks from Massachusetts and the area called us asking for a listing in that city. I've never forgotten it: They pronounced it "WOY-ster," although with the accent it usually sounded more like WOY-stah. It always made me chuckle but in the interest of professionalism we'd all try not to giggle. I loved it though. The accent was fun to hear. We didn't argue. It's their city, they can pronounce it however they wish!