"Southern Germany (German: Süddeutschland) as a region has no exact boundary but is generally taken to include the areas in which Upper German dialects are spoken. ...
That corresponds roughly to the historical stem duchies of Bavaria and Swabia or, in a modern context, to Bavaria and Baden-Württemberg within the Federal Republic of Germany, to the exclusion of the areas of the modern states of Austria and Switzerland. The Saarland and the southern parts of Hesse and Rhineland-Palatinate are sometimes included as well and correspond to the historical Franconia.
Alsace, German-speaking Switzerland, Austria, Liechtenstein and South Tyrol are now not considered as part of Southern Germany but historically, culturally and linguistically, they are related to Southern Germany in many ways. Czech Republic, Hungary, Romania, Slovenia, Croatia, Serbia, Moldova and Ukraine also had large Upper German minorities before 1940s." - (en.wikipedia.org 29.01.2020)