The Yiddish language is over one thousand years old and incorporates German, Slavic, and Hebrew elements and one of the last European languages whose linguistic and geographical classifications remain unclear even after three centuries. The prevalent view claims Yiddish has a German origin, whereas the opposing view posits a Slavic origin with strong Iranian and weak Turkic substrata. The strong relationship between geography, genetics, and languages prompted us to investigate the geographical origin of 393 Yiddish and non-Yiddish speaking Ashkenazic Jews (AJs), Iranian, mountain Jews and over 600 non-Jewish genomes. The Geographic Population Structure (GPS) localized most AJs along major primeval trade routes in adjacent to four villages with names that may be derived from “Ashkenaz.” These are the only placenames in the world derived from this ethnonym. AJs clustered adjacently to Iranian and mountain Jews in support of a common origin. Loss of maternal haplogroups was evident in non-Yiddish speaking AJs compared to the Yiddish speakers. Our results are compatible with linguistic evidence suggesting that Yiddish has multiple origins including German, Slavic, and Hebrew. This is the first study that analyzes genetic data of Yiddish speakers, and it is carried out at a most timely manner as individuals who speak solely Yiddish are increasingly difficult to find.