How reasonably can German cuisine be described as a single unified thing? My mother was from East Prussia and my father from Swabia and their "home" cuisines were pretty dissimilar -- if for no other reason than climate.
Cuisine in Europe is shaped by climate, soil and former political entities. You'll find similar cuisine in and around the alps, along the north sea coast and around the baltic sea. While the people eating the same food speak a dozen different languages.
Same is true for Croatia.. food from Slavonia (near Zagreb) is very different from the coastal regions (Istria and Dalmatia)