North of Poland¹ is known for saying "jo" for "yes".
While in southern Poland² we say "ja".
AFAIK Eastern Poland uses neither. Couldn't find the words even in Kraków lect dictionaries, nor does my grandma from the south-east report ever hearing the word in her home village.
Which seems to line up with Low German and High German respectively.
This is interesting, because Czechia is known to use "jo" again. The dictionaries also have "ja" but it's marked not as colloquial but dialectical. Does any Czech know which dialects use which?
Does your dialect use any of them?
Based on various Internet sources:
¹ Primarily Kashubia. Also Kociewie, Masuria, to a lesser degree also Greater Poland.
² Most notably Upper Silesia (including Cieszyn Silesia), adjacent parts of Lesser Poland (Szczyrk lect dictionary has "ja", but Kraków has nothing, so it has to be the westernmost parts). Supposedly also Bydgoszcz (which is in the north), but all young guys I know from there say "jo", so maybe it's the older generations?