Did the Nazi regime have any particular language policy (such as promoting the use of particular dialects of the German language over others)?

As quoted from /u/daqqer from this thread:

Whenever he give speeches he would use a dialect, preferably used by all Nazis. The dialect was mostly Standard German, but they emphasized the 'r' sound. So, they would have a rolling r if you could say so. In Standard German you barely hear an 'r'. There is a dialect called 'Bühnendeutsch' (stage German) where 'r's are fully pronounced. This dialect is used by actors because words need to be pronounced more clearly on stage in order for the audience to understand every word correctly. On top of that the Nazis always screamed when on stage in order to appear powerful. There is a secret tape of Hitler speaking on a private occasion. How he spoke in private situations was a long mystery. His voice was actually pretty calm and he only had a slight accent - probably more Bavarian but definitly not Austrian.