Yiddish a Slavic language

Dr. Wexler [Dr. Paul Wexler, a Tel Aviv University linguist.] uses a reconstruction of Yiddish to argue that it began as a Slavic language whose vocabulary was largely replaced with German words. Going even further, he contends that the Ashkenazic Jews are predominantly converted Slavic and Turkic people who merged with a tiny population of Palestinian Jews from the Diaspora.

While few linguists are convinced by this radical hypothesis, the notion of a Slavic origin for Yiddish is being taken as a serious challenge to the field. "Even if he is not absolutely right," said Dr. Jacobs, "we are forced into a discussion of the issues he has raised."

- Scholars Debate Roots of Yiddish, Migration of Jews

see Where did Yiddish come from and the original article.