> IIRC Polish mathematicians were close to being the world's best prior to WWII

That's right. The Lwów-Warsaw School, the Warsaw Schools, the Kraków School, and so on were big during the interbellum. There was a good deal of activity in the space of mathematics, logic, and philosophy within that scope (art, theater, film, literature, etc. had their respective flowerings).

However, what I had in mind was that education has always been important, with formal education beginning in the Middle Ages with the first cathedral/collegiate schools. And because Poland became increasingly republican in nature, demanding skillful articulation, argument, and diplomacy as a matter of statecraft, Latin culture was of such a high standard that, during the Renaissance and early modern period, foreigners would comment that they felt as though they were visting ancient Rome given the high level of Latin proficiency. I should also mention that the world's first ministry of education was founded in Poland in the 18th century during the reign of Stanislaus II Augustus, creating, among other things, the first comprehensive, state-mandated natural science curricula.

During the subsequent partitions and foreign occupations when germanization and russification campaigns were inflicted on the populace and severe restrictions on the Polish language were put in place, clandestine home schooling, underground education networks, and "floating universities" allowed the culture to survive. So it has a deeply-ingrained and special importance across a range of concerns, from Scholastic libertas to senatorial virtus to cultural survival to so-called "positivist" industry.

> Given how strong Poland used to be in mathematical logic, I can see an alternate history line where WWII does not happen and first computers are developed in Krakow and Lwow.

Indeed. Further evidence of this is that even under the restrictive and crippling policies of the communist state and Soviet influence, you still had a surprising amount of innovation in this space.

> But computer programming with Polish keywords would indeed be a bit of a hell ;)

What would really be delicious is an inflected, synthetic programming language. ;)