Plus the questions were so hideous,
I checked them out, they ask for declensions and I simply don't remember them by heart. You're not speaking language by thinking ah and here I should use a such and such form of a verb a singular nominative case or whatnot...
I think those test were devised to catch out native speakers of the language, so you have done very well indeed.
the native Silesian
I don't see the problem they can use their own version of the Polish language. Why not? That school of linguistic purism that took over in Poland for more than century is just silly.
Educated people with class will be always speaking a proper Polish whereas all the rest will either speak Silesian which is amusing, sounds nice and is refreshing or create distorted version of 'pure' Polish as we can see on TV. Especially some politicians speak that language badly, with something I call an accent from a gutter. Others are not much better, taking too fast, without a proper rhythm and measure.
I take an authentic regional version of the lingo every day over that pol-soviet newspeak. A poor excuse for a language.