The assumption that nation=state=language, one and indivisible, is a relatively recent and rather limited/limiting idea. In the great historical empires (Egypt, Alexander, Rome, Byzantium, the Ottomans, the Persians) rulers and ruled never necessarily shared the same language. English as we know developed after centuries of a French-speaking feudal class controlling territories and lands across most of modern France as well.
The language, culture and concept of Germany long pre-dated the idea of a German nation-state as we understand it now. The Holy Roman Empire was often referred to in German as the Holy Roman Empire of the German Nation (as the inheritor to Charlemagnes’ Empire), though quite a few of its participant rulers ruled over those who spoke other languages. The Hapsburgs acquired huge ranges of territories* (more by dynastic marriage than conquest, it seems), and when the HRE disappeared and they reinvented themselves as the Austrian (later Austro-Hungarian) Empire, it was still a vast collection of different ruling arrangements in different territories with different languages; but the Austrian core was always of German culture. A united Germany was the latecomer.
*By chance I came across this list of the titles attributed to the Hapsburg Emperors in the 18th century:
*Karl VI, Roman Emperor and German King, King in Castile, Aragon, Leon, the Two Sicilies, in Jerusalem, Bohemia, Dalmatia, Croatia, Slavonia, Navarre, Granada, Toledo, Valencia, Galicia, Mallorca, Seville, Sardinia, Corsica, Cordoba, Murcia, Jaen, Algarve, Algeciras, Gibraltar, of the Canaries and West Indian Islands of the American Continent, and King of the Atlantic Ocean; Archduke in Austria, Duke in Burgundy, Brabant, Milan, Styria, Carinthia, Krain and Limburg, Luxembourg, Geldern, Wurttemberg, Upper and Lower Silesia, Calabria and Athens, Prince in Swabia, Catalonia and Asturias, Margrave of the Holy Roman Empire in Burgau, Moravia, Upper and Lower Lausitz, Prince-Count in Habsburg, Flanders, Tirol, Pfirt, Kieburg, Gorz and Artois, Landgrave in Alsace, Margave in Christano, Count in Namur and Roussillon, Lord of the Wendish March, in Portenau, Biscaya, Molins, Salins, Tripolis and Mechelen, *