When written with German spelling instead of english-like, German speakers could understand them. Yiddish/Jiddisch can be full of loans from slavic languages in the east, or still very close to German. Depends where the community originates from. During and after the WW2, Jews from divers geographic origins met in their new countries, but with the common high-German grammar and the hebraic vocab, Yiddish still kept a good common base all over. Not difficult to learn/understand for German speakers. One notice that Entrundung (unrounding of vowels) is a general phenomenon in Yiddish, like in many dialects of German (lower Alemanic, some Bavarian, some palatinian...)

A nar git, a kluger nemt.
==A fool gives, a wise man takes
A Narr git, a kluger nemmt.

A goldener shlisl efent ale tirn.
A golden key will open every lock (door).
A goldener Schlissel effent alle Tiren

Nit dos iz sheyn, vos iz sheyn, nor dos, vos es gefelt.
==Beautiful is not what is beautiful, but what one likes
Niet dos is scheen, wos is scheen, nur dos, wos es gefällt.

Vos lenger ein blinder leybt, dos mehr seht er.
==The longer a blind man lives, the more he sees.
Wos länger ein blinder leebt, dos mehr seht er.

Ainer iz a ligen, tsvai iz ligens, drei iz politik.
==One lie is a lie, two lies are lies, but three is politics!
Einer is a Ligen, zwei is Ligens, drei is Politik.