You totally can. Languages, cultures, history -- they die every year in droves. It's more troublesome (both from a logistic and moral standpoint) to induce that sort of loss, but it's also fairly trivial -- just get the kids and keep them from learning about the history and culture in question. Keep that up for one, two generations and it'd be dead. A nation without people to remember it and live in its ways is nothing.
That's... Not as easy as you seem to think. Morality-wise, well, Germans tried to do that multiple times, Russians as well, so you can usually find someone willing, but logistically... That's a freaking nightmare worse than conducting land war in Asia. You either have to physically remove virtually all children of a given culture from all adults of the same culture, permanently... OK, there is no second option. You have to physically create life-long concentration camps with unparalleled security measures and keep them up for about two generations.
You see, both Germany and Russia were trying to do kill Polish culture and language for about 123 years. And yet here we are.
Than again, I'm positive that there are more languages dying than being born, but:
a) I think it is a good thing (less foreign languages to learn, and still more than enough to study for a lifetime),
b) None of them are actually wide-spread in any sense of the word, as far as I know, and if I'm mistaken in that, please provide examples.
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In other news, we have had presidential elections in Poland yesterday, on 10th of May, Sunday. There will be second turn in two weeks for sure (we have the system where if there is no-one with 50%+ votes in the first turn, we have second one with two high-runners), but so far results are certainly interesting.
First place: Andrzej Duda, our major counter-candidate. About 35 - 40 %.
Second place: Bronisław Komorowski, our current president. About 30 - 35%.
Third place: Paweł Kukiz, our well-known rock singer. Yeah, rock singer. With very anti-system approach, he gathered a bit over 20% votes.