So? Austria is just south of Germany.
Big taboo to confuse the two! It's like mixing up the Dutch with the Belgian or the Serb with the Croat. Or confusing Canada with the US of A...
Well, Dutch and Gelgians speak different languages, as well as Serbs and Croats. Austrians speak German. And the vast majority of Canadians speak American, albeit with a funny accent.
And those in the South (you know, Georgia, the Carolinas, Alabama, etc., etc., etc.) speak American, too, albeit with a funny, but often charming (when not downright irritating) accent.