But for a temporary language, Yiddish was old, almost as old as some European tongues. Jews first began to develop it from the German dialects spoken in the cities when they pushed up from France and Italy into German-speaking Lotharingia. Old Yiddish (1250-1500) marked the first contact of German-speaking Jews with Slavic Jews speaking a dialect called Knaanic. During the 200 years 1500-1700, Middle Yiddish emerged, becoming progressively more Slavic
