Can we make isoglosses?

[Koen G]

Not to mention that the goat milk fits rather well with the billy goat liver.

This is why it would be interesting to get some more clarity about the area of these dialectical features. So far I've noticed:

* bock -> pock: devoicing /b/ to /p/ seems like the most common of the three. For example I remember Diebold Lauber (Alsace) using "Diebold" and "Diepold" interchangably. And "pock" for "bock" is not hard to find. Here is one example I found in a few minutes on google, the poetry of Oswald Von Wolkenstein (South Tyrol): You are not allowed to view links. Register or Login to view. 

* Geis -> Gas: This is more difficult, but it certainly exists. All examples I can find in a quick search are 1800 or later, all from Austria. "Gas" seems to belong to a more limited area than "pock", but I don't know yet if and where they overlap.

* Milch -> Mich: we don't even know if this really exists as a dialectical form. If it doesn't, the "goatmilk" reading can only survive by assuming "mich" is either an abbreviation or a mistake.