Yiddish originated in Germany, but was eventually spoken by Jews all over Europe.
In its 1000-plus-year history, the Yiddish language has been called many things, including the tender name mame-loshn (mother tongue), the adversarial moniker zhargon (jargon), and the more matter-of-fact Judeo-German.
What is Yiddish?
Literally speaking, Yiddish means "Jewish." Linguistically, it refers to the language spoken by Ashkenazic Jews--Jews from Central and Eastern Europe, and their descendants. Though its basic vocabulary and grammar are derived from medieval West German, Yiddish integrates many languages including German, Hebrew, Aramaic, and various Slavic and Romance languages.
The Origin of Yiddish
It is impossible to pin down exactly where or when Yiddish emerged, but the most widely-accepted theory is that the language came into formation in the 10th century, when Jews from France and Italy began to migrate to the German Rhine Valley. There, they combined the languages they brought with them, together with their new neighbors' Germanic, producing the earliest form of Yiddish. As Jews continued to migrate eastward--a result of the Crusades and the Black Plague--Yiddish spread across Central and Eastern Europe and began to include more elements from Slavic languages.
In Ashkenazic societies, Hebrew was the language of the Bible and prayer, Aramaic was the language of learning, and Yiddish was the language of everyday life. Scholars refer to this as the internal trilingualism of Ashkenaz. Though they vary in sound and use, all three languages are written in the same alphabet.
The first record of a printed Yiddish sentence is a blessing found in the Worms Mahzor (Vórmser mákhzer) from 1272. Beginning in the 14th century Yiddish was commonly used for epic poems such as the Shmuel-bukh, which reworks the biblical story of the prophet Samuel into a European knightly romance.