What are some words that sound the same or very similar in other dialects but have different meanings?
Prawie
In standard Polish "prawie" means "almost" but in my dialect (and Upper Silesian dialects) it means something along the lines of "exactly, precisely, actually, at the moment".
So if I said "Prawie zdążyłem przed deszczem" – "I just made it before the rain", it could get misinterpreted by speakers of other dialects as "I almost made it before the rain".
Zaś
In Upper Silesian and Western Lesser Polish dialects it has the meaning of "again", but Poznań dialect uses it as "later".
So our "Zaś to zrobię" – "I'll do it again" would mean "I'll do it later" for speakers of Poznań dialect.
In standard Polish, however, it only means "meanwhile, whereas".