For someone learning English, the first thing I think of is the aunt of a lady that I took Norwegian classes from. My teacher said it's really common in Norway for families that can afford to do so to send their kids to a summer camp in the UK when they're around 14 or so, where they only speak English for a few months to really polish their accent and fluency. Her aunt's parents were a bit behind the ball, though, and all the English summer camps had already filled up by the time they tried booking a place for her, but they found a camp still taking applications in Arkansas. So, all her other relatives speak with posh, British accents, and then her one aunt rolls into the room, talking with a heavy twang that throws everyone off.