Take the word "mad".
In England it means more like "crazy" and in American English it tends to mean "angry". In Europe they will base a whole new language on these kinds of regional differences. They are just nuts there and you can see why they butcher themselves and to outsiders these two factions look identical and sound identical.
Russian and Ukrainian are related but are two separate languages since the Ukrainian language sounds softer than Russian and uses a slightly larger alphabet. Ukrainian has some different grammar rules - for example, an additional future tense, an additional past tense, a way of using adverbs that would be strange in Russian, and some other different syntax features. It has some sounds that don’t exist in standard Russian, like the h in hryvnia and the yi in Ukrayina, the name of the country; also, the e sound is used in Ukrainian much more frequently while in Russian it would be ye.
When Russians start playing the bandura then maybe I’ll consider them the same people: https://www.youtube.com/watch?v=zJeBgeMcuyc
https://www.youtube.com/watch?v=1KAHyuVjjmg
The Russian commies tried to murder every single person who played the bandura in the 1920s and 1930s.
Even the Ukrainians are blown away when someone can play it well: https://www.youtube.com/watch?v=cdmp99xXBgU