I've changed language in registry to pl_PL and locale folder en_UK to pl_PL. Couldn't launch the game through steam because language changes to English by default so I had to use .exe in folder.
I've installed patch and voilà, it works like a charm. Welp, I just took the language file global.res from locale folder and changed pl_PL to en_UK once again so I can launch game through steam. CASE CLOSED LMAO