Can we make isoglosses?

[ReneZ]

Where my research has taken me.
If I follow all the clues that can be traced, I will end up in an area.
I also have to say that it can't get any worse.
The coordinates are in the picture.
If I assume that a mountain range forms a language border (like the Gotthard example), then this mountain range also forms one. The language distribution took place via the valleys and rivers.
Exactly at these coordinates there is a breakthrough.
Here above in green Southern Bavarian, blue Italian, yellow Slavic and brown general Romance dialects.

If the place of origin is indeed in this environment, then we have more than an ass on our hands as far as the translation of the VM text is concerned.

Ah, I've been there :-)
For what it's worth, it fits with the pink circles in Koen's map.

BTW, I think you meant ace, not ass...