Which Regional accent is the most difficult to understand even as an American?

Posted by UsamaBhai_101@reddit | AskAnAmerican | View on Reddit | 865 comments

My native language is not english but still I consider myself to be proficient in speaking English. Recently I saw a youtube documentary about english dialects and it completely caught me off guard withsome of the accents. There were accents like "Cajun" and "Appalachian" really made me feel like it was another language lol.

It made me curious, are there more regional accents like this that are difficult to understand if you're not a native speaker or even for Americans?