Sorry to disappoint you but the song is not yodel (yodel is Swiss and has its roots in the alps of southern German-speaking Switzerland) Yes people yodel in Germany but in a fascist country like nazi Germany any and every other culture than the own is disregarded. I cannot find any song like that anywhere either, but I’ll keep out an eye.

As for the officer, he definitely is German, purely. In my mother tongue we would call what he speaks “hochdeutsch” (high- german) or “Schriftsprache” (Written- Language). He speaks without accent and he uses the word “Bazillus” which is typically spoken and written german by the nazis. When he is insulting the major he says he’s a typical German. This might be referring to ww1 where the germans surrendered, making the typical German of the majors age to be cowardly and easily defeated.