At http://archaeologynewsnetwork.blogspot.co.uk/2016/04/dna-analysis-sugges… … a dna analysis, it is claimed, has shown that Yiddish, the old language of the Ashkenazi Jews, had its origins in NE Anatolia. Yiddish was developed by Iranian and Ashkenazi Jews as they travelled the Silk Road (s). Yiddish has Iranian, Turkish and Slavic words and contains 250 words for the term 'to buy' and 'to'sell' – suggesting it was the language of merchants. Modern yiddish also contains words from Germanic languages which it required after the Ashkenazis moved west into central Europe, as well as Slavic and Hebrew. It is written in Aramaic letters. The theory now is that it was mainly Slavic but over time shed a lot of these and substituted them with German words (as part of the Austro-Hungarian empire).
The findings are published in Genome Biology and Evolution and the authors go on to say that around 900 to 1000AD the Ashkenazis probably relocated in Kharazia, a Turkish ruled kingdom that dominated central Asia for the next 500 years. Kharazia then came to an end and the Ashkenazis moved westwards, towards Europe (including Russia), where they have been an important element of the population of eastern and central Europe.