have difficulty understanding different dialects in China.
Polish and German are not considered dialects but are languages although they do come from Indo European linguistic group of languages.( latin alphabet, )
They share some similarities in grammatical structures and sometimes in vocabulary but they sound even more different than the Shanghai dialect would sound to someone speaking Mandarin .Cantonese
and Mandarin would be like German and Polish.
If you speak English, no problem in big cities( no warrantee in the country side and with old people like everywhere else) in Poland and among the youth.
The Polish speak English but the English seldom speak Polish!
In Europe the English are lucky because everybody speaks their language, for them it is something obvious. ( English is definitely easier than Polish too!)