Every visit to the Oktoberfest or to a Biergarten raises questions about how to translate Bavarian dialect into English, the same goes for Bavarian to German, but there are a host of dictionaries to help in that case. There are also some which translate “Bairisch” to English, for example the „Bavarian into English. A Lexical and Cultural Guide" by the late professor Otto Hietsch from Regensburg. The three volume book not only teaches language, but also gives insights to the Bavarian way of life. Among the achievements of the professor is the translation of Himmiherrgottzaggramentzefixallelujamilextamarschscheißglumpvareggts, in English the word simply means goshalmightysakesalivegloryshovitshitpissandcorruption.
Below are some other words you need to understand.
Leberkäs: meat loaf
Leberknödel: liver dumpling
Bierbauch: a protruding abdomen assumed to be caused by a surfeit of beer
Obazda: cheese clump; a spread made of cheeses, butter, egg yolk and spices
Arschbacke: either of the two fleshy parts of the body on which a person sits
Schuhplattler: a native Alpine clog dance
You can find a few more examples here. You can also get a lesson from Loddar here.