Here in Arizona, there is a town about 100 miles north of Phoenix called Prescott. It's not pronounced "Pres-scott," it's "PRES-kit." (You almost don't say the O at all.) My friend Steve in California very briefly was considering buying a house as an investment there and once wanted me to pick up some real estate brochures about Prescott. I told him in a letter that I mailed along with the stuff that if he talks to a real estate agent there, "make sure you pronounce it PRES-kit, otherwise the agent will figure, 'Gee, this dummy from out of state who can't pronounce it right ought to be worth an extra 20,000 bucks!'"
Another pronunciation stumbling block for non-Arizonans is the big cactus plants in the desert called "saguaro." (These are the kinds of cactus that you see on Road Runner cartoons.) The correct pronunciation is "suh-WAR-row," pronouncing the G like a W. Of course, many visitors to Arizona call them "sagwaros" or even "cigaros." When I run into these people visiting the nursery I work at, I gently tell them that it's pronounced "suh-WAR-row" and jokingly tell them to make sure they use the correct pronunciation, otherwise they might as well have a flashing sign on their forehead blinking, "TOURIST! TOURIST! TOURIST!"