Considering Guardiola took weeks of intense German lessons before arriving to Bayern, they speak German.

Central Bavarian along the main rivers Isar and Danube, spoken in Upper Bavaria (including Munich, which has a standard German-speaking majority), Lower Bavaria, southern Upper Palatinate, the Swabian district of Aichach-Friedberg, the northern parts of the State of Salzburg, Upper Austria, Lower Austria, Vienna (see ...