After my question What happened north of the Alps after the romans "left"?, I read through the sources given by the comments and answers. One paragraph in this post was especially interesting to me:
West of the Enns there was also cultural continuity. Until the Middle Ages the Romance-speaking population retained Christianity, Roman legal concepts, and certain elements in music and painting. Salzburg and Passau are thought to have still had a Romance-speaking population in the eighth century, from which the composers of early charters were drawn. The fact that the name “Norici” was used in reference to the Bavarians indicates the survival of a substantial Romance population in that area.
Sadly I cannot find the sources to these claims.
During my research I found this webpage (in German; seems to be down, available here) which claims that old Bavarian was not a Germanic language but a Romance one. This hypothesis is based on house and place names as well as modern "typical" Bavarian words being more easily explainable from a Latin root and it does seem to make sense, but it is still speculation. Respected linguists such as Prof. Rowley (who was contacted by the owner of the website and replied [p1, p2, p3]) argue that, while some words may come from Latin, most linguists agree that old Bavarian was a Germanic language. edit: because of a comment from DevSolar I read this text again and see that it is irrelevant to the question. I had posted it because it is interesting.
The Wikipedia page on old Bavarian (in German) describes how the language evolved without linking to specific sources. It also contains a list of texts which are presumably old Bavarian. This still does not convince me since there is no explanation as to why those documents are considered old Bavarian. I have not read the books that are linked in the sources and sadly I do not have the time to read so many books for the few pieces of information I am looking for.
I do not argue for or against the established opinion on this topic. I simply want to know the truth and do not trust any opinion without knowing the source myself.
For my question (see title) I would like primary sources (such as texts that explicitly talk about the language of the region at that time), preferably with an evaluation of those sources by respected linguists and historians on how the Latin (or Romance) language died out (or merged).
Especially I would like to be answer the following questions:
- what are the sources for the claim that a Romance speaking population had survived into the 8th century (or perhaps even longer?)
- when was the point at which one could talk about a population which spoke the same language?
I was not sure if this would fit better into the history or the linguistic stack, so please move it if you think it would be a better fit elsewhere.