The origin of the Yiddish language (spoken at least since the 9th century A.D.), and consequently Yiddish speakers, has been debated for the past several centuries, mainly between linguists. While the Rhineland hypothesis suggests a German origin, the Irano-Turko-Slavic hypothesis, proposed by Paul Wexler, suggests a more complex origin starting with Slavic lands in Khazaria, followed by Ukraine, and finally Germany where the language was relexified, i.e., adopted a German vocabulary, but retained its Slavic grammar, which is why Yiddish was oftentimes called “Bad German.”
To evaluate these two hypotheses we applied the Geographic Population Structure (GPS) tool to the genomes of over 360 sole Yiddish and non-Yiddish speaking Ashkenazic Jews. This is the largest study of Ashkenazic Jews and the first one to study Yiddish speakers. Surprisingly, GPS honed in an obscure region in northeast Turkey. There we found four primeval villages (one was abandoned in the mid-7th century A.D.) whose name may be derived from the word “Ashkenaz,” suggesting that this was the central location of ancient Ashkenaz.
GPS coordinates provided by analyzing the DNA of Ashkenazic Jews overlap four ancient villages whose names may be derived from the word Ashkenaz
Our full study has been published in Genome Biology and Evolution:
Das R, Wexler P, Pirooznia M, Elhaik E. Localizing Ashkenazic Jews to primeval villages in the ancient Iranian lands of Ashkenaz. Genome Biol Evol. 2016. doi:10.1093/gbe/evw046.