20th Century
In the early 20th century, especially after Socialist October Revolution in Russia, Yiddish was emerging as a major Eastern European language. Its rich literature was more widely published than ever, Yiddish theatre and Yiddish film were booming, and it for a time achieved status as one of the official languages of the Ukrainian People's Republic, the Belarusian and the short-lived Galician SSR, and the Jewish Autonomous Oblast. Educational autonomy for Jews in several countries (notably Poland) after World War I led to an increase in formal Yiddish-language education, more uniform orthography, and to the 1925 founding of the Yiddish Scientific Institute, YIVO. Yiddish emerged as the national language of a large Jewish community in Eastern Europe that rejected Zionism and sought Jewish cultural autonomy in Europe. It also contended with Modern Hebrew as a literary language among Zionists. In Vilna there was intense debate over which language should take primacy, Hebrew or Yiddish
Yiddish changed significantly during the 20th century. Michael Wex writes, "As increasing numbers of Yiddish speakers moved from the Slavic-speaking East to Western Europe and the Americas in the late 19th and early 20th centuries, they were so quick to jettison Slavic vocabulary that the most prominent Yiddish writers of the time—the founders of modern Yiddish literature, who were still living in Slavic-speaking countries—revised the printed editions of their oeuvres to eliminate obsolete and 'unnecessary' Slavisms." The vocabulary used in Israel absorbed many Modern Hebrew words, and there was a similar increase in the English component of Yiddish in the United States and, to a lesser extent, the United Kingdom. This has resulted in some difficulty in communication between Yiddish speakers from Israel and those from other countries.
Read more about this topic: Yiddish Language