Odd, I don't speak Polish, but my mom and grandparents did. Even that small exposure was enough for me to get that pronunciation 100% correct. I wonder what the minimum exposure to any given language is to allow someone to correctly guess pronunciation. I speak a little German and French but regularly get the pronunciation incorrect, but I didn’t grow up around native German and French speakers.
Polish pronunciation is actually incredibly easy, there's a direct mapping (a mathematical function) from a simple partition of letters to phonems. Unlike in English, where we have weirdnesses like "vehicle" or "colonel". There's a price to pay for quick and massive import of words, lack of centralized language development coordination body and conquering the global stage of accents, I reckon.
Example for the town: Mszczonów -> Mshchonooff (Americanized).