"Yiddish was the European language most directly affected by Nazi rule. Although linguistic assimilation had become the norm by the 1930s among Jews in western Europe, the Soviet Union, and the United States, it was slowed in Poland by some of the external and internal forces of exclusion and renaissance alluded to in the previous chapters. Thus, Yiddish was the main language of the ghettos, and of the majority of Jews targeted for annihilation, though most Jews also knew at least one coterritorial language."