Your German may be decent, even fluent. But will you understand locals in Frankfurt? Here's a little dictionary for your amusement ;-)http://www.frankfurt.de/fm/870/hessisch_englisch_lexikon_dt.pdf
Süüüüüüüüüüüß :-)
The dialect really gives a different flavour. Makes a true translation really different. I realized that after reading Jakob Arjouni's "Happy Birthday, Turk" in its English translation. Neat story, but the humour was completely lost in translation, in large part because all the "hessisch" was gone in the dialogues. Fortunately, Arjouni got a different translator after his books became bestsellers. Anthea Bell, who also translated Asterix from French into English, did a much better job preserving the humour in the later translations.