It's not quite German either. E.g. פֿרויען / froyen ("women") represents the Yiddish pronunciation, which would be rendered "Fräuen" in German orthography, whil

It's not quite German either. E.g. פֿרויען / froyen ("women") represents the Yiddish pronunciation, which would be rendered "Fräuen" in German orthography, while the Standard German cognate is "Frauen". So it seems to me like no attempt was made to represent the German pronunciation of the word and the familiar Yiddish spelling was retained instead. (Other features, like not distinguishing between German "i" and "ü" could perhaps be explained by Austro-Bavarian German also not distinguishing these.) By the way, as a German speaker who can kind of read Yiddish except for Hebrew and Aramaic loanwords (i.e. kosher, khale and kashrut, though כשר was guessable from context), I'm curious which of the German words you couldn't understand.