Accent =/= dialect, though it is part of it. But you'll have to do a lot better than that to argue for separate language. "Phonetic" eye-dialect spellings only confuse the issue. If after a little exposure the speech is mutually comprehensible, then its dialect, I'd think. Those what allegedly can't understand likely lack the exposure.

Keep in mind that a lot of American English speakers will claim they can't understand English English (whatever dialect), but who is saying they are different languages?