Yiddish is a mirror of Jewish history, thought, and practice--for better and worse. Karlen charts the beginning of Yiddish as a minor dialect in medieval Europe that helped peasant Jews live safely apart from the marauders of the First Crusades. Incorporating a large measure of antique German dialects, Yiddish also included little scraps of French, Italian, ancient Hebrew, Aramaic, the Slavic and Romance languages, and a dozen other tongues native...