Вот один вежливый юзер пишет : "I've taught myself to say "Appalatchian Trail" in the south and Appalaychian Trail in the north. Being polite is usually better than having to be right."
Еще цитата "apple at cha Is the way I pronounce it and I live next to a town named Appalachia and everybody calls is apple at cha."
И еще такое мнение
The pronunciation of "Appalachian" in Colorado is "Foothills".