[jwr]

I am a native Polish speaker as well, and I can understand the texts very well, but I think they might be more difficult for younger readers, who did not learn any Russian. It seems to me that Polish has drifted away from most other Slavic languages.

As an example, without learning any Russian you have no chance to understand "govorju" which is like the Russian verb "govorit'", which is "mówić" in Polish.

One thing I found interesting is that the cyrillic versions are actually easier to read, as many Slavic sounds can more easily be represented (like "ч" or "щ").

[rimliu]

To anecdotally confirm this point: I am not a native Russian speaker, but I am fluent and Russian, and I am also very familiar with Polish (it's complicated). Those texts are very readable to me, so knowing Russian and Polish is likely to cover the widest base.

[yeellow]

You could guess it from "gaworzyc" though. But I agree that knowing some Russian helps.