If you think the U.S. does not have regional dialects think again. This wonderful dictionary will convince you otherwise. Once you start reading the entries you will not be able to stop; bubeleh, bugger, bumps, cack, chickie, codger... It is a joint project of the American Dialect Society, the University of Wisconsin, Madison and Harvard University Press. Don't take my word for it. Read this review "What's In A Word? A 'Dictionary' of Americanisms" by Amanda Katz, or listen to this interview about DARE on the Diane Rehm Show.
The complete Dictionary of American Regional English is available in the Olin print Reference Collection.