[vidarh]

It's tricky because the pronunciation in English and Scandinavian languages (no idea about Polish) would be pretty much the same between OK/ok and okay/okei/okej (Swedish also uses okej; Norwegian okei) unless you spell out the "OK" which you sometimes do, sometimes don't in Norwegian at least (it's hard to tell because people might spell it out using English pronunciation), but my feeling is that especially if you intend the letters "O.K.", whether or not you spell it out, it tends to have a more positive, confirmatory sense, while if you use the word "okei" in Norwegian, you have more room to alter the pronunciation to imply sarcasm or doubt, e.g. stretching the syllables.

I wonder if that may play in with other languages too. I think I'd be inclined to type out "okay" if I wanted a better shot at conveying that same thing in English in writing, perhaps with some ellipses. Eg. "Okay... But .." rather than "OK... But" or "OK, but". Maybe just because the short, abrupt "OK" feels more like it must mean certainty. This may very well be entirely personal, though, and I have no idea if others would notice the distinction.