I’ve just come back from my Irish Set Dance group. Set dances are called by someone and here in Hamburg we use a mix of English and German. The step names are mostly in English – I’m not sure that there any books that explain the steps in another language – but there are moves where German is used. So you might here »Ladies Chain und dann umdrehen« meaning “Ladies Chain and then turn around” or »Ein halves House« – “Half a House” – which is particularly interesting because of the inflected form of the word halb to match the German word for “house” – das Haus. One also learns words like schwindelig – “dizzy” (from all of that umdrehen) – and die Pause – “the short break” – that aren’t dance specific.
But probably most importantly, I think that dancing acts a little like alcohol is meant to, it relaxes you and you are more willing to give German a try. It helps too that you laugh when steps get screwed up, at least in my wonderful group, because laughter is a great learning accelerator!