At the turn of the twentieth century, operatic singing in the German-speaking world remained deeply influenced by the Italian tradition, which implied a lyrical vocal style that prioritised technical precision, tonal beauty, and expressive clarity. From the 1910s onward, composers increasingly and systematically explored vocal techniques that blurred the boundary between speech and song, referred to here as the 'hybrid voice'. These approaches emerged from a complex interplay of symbolic, aesthetic, political, and philosophical influences and reflect a search for more diverse and individualised modes of vocal expression. This Element examines the hybrid voice in four seminal works of German modernism: Alban Berg's Wozzeck, Kurt Weill's Aufstieg und Fall der Stadt Mahagonny, Bernd Alois Zimmermann's Die Soldaten, and Adriana Hölszky's Bremer Freiheit. By situating each work within its historical and stylistic context, it traces a broader musical trajectory in German opera from expressionism and new objectivity to the postwar avant-garde.