I suppose if it's comparable to what we have in the U.S. (regarding Spanish speakers), it might not be that bad. I guess it just depends on how it is in practice. The language issue has been somewhat contentious in the past several decades, particularly in the realm of bilingual education, but there have been also those who have balked against bilingual voting ballots and businesses that have "press 2 for Spanish." Some have called it a rights issue and believe that any attempt to pass any "English only" legislation is racist against Hispanics.
It's a completely different situation. Hispanics are migrants, they deliberately move to the US, an English-speaking country.
Donbas people are Russian people who have spoken Russian since the times of Catherine the Great and ended up within the territory of Ukraine, when Ukraine was created by Stalin.
There was no problem until 1991 because the official language of the USSR was Russian.
But in this era they passed a law that imposes Ukrainian on Russian-speaking people.
That is how they became separatists.
I provided the example of South Tyrol where most people speak German, as you can see in the map.
It's a German-speaking province in Italy. Where people don't have to learn Italian, because German is the official language.
So German-speaking people can speak German anywhere: at school, in the university, in the Town Hall, etc...
they need no Italian-learning at all. Anywhere
If someday the Italian Government forbade South-Tyroleans from speaking German, it's normal that separatists would rise up and protest en masse.
And it's natural that Austria and Germany (but Austria in particular) would support them.
If the Italian soldiers massacred the separatists, it's normal that Austria would invade Italy to rescue them.
Having heard both Russian and Ukrainian spoken, they appear to be mutually understandable, for the most part. They just appear to be different dialects, just like English would sound different in London, England as opposed to Dallas, Texas. For the most part, they would still be able to understand each other, as well as the slight orthographic changes and different word choice.
Yes, they are very similar, with some differences about pronunciation, alphabet and vocabulary.
Yet Russians are very proud of their own language and don't want to learn a language in a Donbas that has always been Russophone since the times of Catherine the Great.
So, I guess I would wonder if they have some sort of equivalent to bilingual education in the Donbas. Do Ukrainian businesses offer the option of "press 2 for Russian" if a Russian speaker is calling them? Do they have voting ballots and other official documents in both Ukrainian and Russian? Did the Ukrainians ever make any linguistic accommodations for Crimean Tatars when they still had control of Crimea?
When Donbas was part of the Ukrainian state, they had to learn Ukrainian. They could use Russian as second language of course, but the first language was Ukrainian.