The one thing I learned from the Ukrainian and Polish elders in my life: the people in the next village are idiots and have no idea how to make proper pierogis.
I have a theory about language, which I've formulated by living all over the world for 50 years.
It goes like this: If you have two villages, maybe separated by a lake, or by a mountain, and one village has goats, the other has sheep - or maybe one of these villages has brown goats and the other just white goats - or maybe there are a couple of cows in one and a coal mine at the other - then it doesn't matter how close these villages are, they will fight for their own dialect, which will eventually become a new language.
The real question is how the Polish/Ukrainian elders feel about those Ukrainian/Polish elders and those weird things they eat, because ‘those sure as hell are NOT pierogis!!’ Or worse ask the Romanian elders in my life and they’ll gladly tell you no one but there mother makes colțunași right, let alone foreigners (which of course includes the family up the street).