Yiddish is well represented by written texts starting at about 1400. There are some earlier traces of written Yiddish that go back about 1000. It would seem that the trail goes cold at that time. However, if we accept the evidence presented on this blog that Yiddish is descended from Gothic we can venture further into the past, as far back as somewhat before 400 when Gothic is documented by Wulfila's translation.
Around 400 Yiddish would not have been very different from Gothic as represented by Wulfila. By 1400, Yiddish shows very strong influences of German. What can be said about the intervening period?
Let's look first at geography. Around 400 Yiddish speaking territory would have coincided with at least a part of Gothic territory. This territory embraced the northern shore of the Black Sea, including Crimea, and extended into the Balkans. By the 800's Ashkenazic Jews, presumably Yiddish speakers were living in the Carolingian Empire, in Austrian and Bavarian territory, notably in Regensburg. If this community was an extension of the Gothic Jewish community it mostly likely spread there from the Balkans.
In the course of the following two centuries, Jewish communities spread into East Central German towns like Magdeburg, Halle, and Erfurt and in the central Rhineland around Speyer, Worms and Mainz.
Next let's look at social conditions. During the late Roman and early Medieval period up to about 800, Jews were generally well integrated into European society and Judaism even attracted many converts. Later conditions deteriorated, particularly after the late 11th century.
These changes very likely had linguistic consequences. During the early period up to 800, Yiddish may have served the role of a missionary language designed to recruit converts. Traces of this early function still survive in Yiddish as I plsn to demonstrate in a later post. When Jews came in contact with German-speakers, chiefly after 800, Yiddish which was then based on Gothic would have been close enough to early German for Jews to be able to communicate with their neighbors by making small modifications in their speech. This would have chiefly meant that Geman sounds would be substituted for Gothic based sounds. Among themselves. Jews would have continued to use the Gothic based pronunciation.
This state of affairs where a community uses one system internally and communicates with neighboring communities through sound substitutions is called a diasystem. It is likely that this diasystem persisted until about 1100. Around this time the social status of Jews began to fall and the German sounds came to be used all the time, even in inter-Jewish communication. This collapse of the old diasystem left a very strong mark on later Yiddish, something that I plan to make the subject of future posts.