That's a problem a much bigger country like China doesn't really face surprisingly, despite having central planners, and despite having plenty of different nationalities! Maybe Euros could learn a bit from them and democratic centralism too
China is only interested in its minorities as a means to promote tourism. Horrible example. Children are put into boarding schools in many places where they are forced to use Mandarin.
It is currently bussing in lots of Mandarin speakers into Hong Kong to undermine Cantonese. It has done a good job of undermining Tibetan as well.
China will destroy or subsume all native culture in every nation/land it gains control of. China is following the Colonial model of divide, conquer/conquest and containment, except this is all happening in the modern era.
What's bad? They're being punished if they speak their native language and are taken away from their home communities. No better than the stupid boarding schools minorities were sent to in the west.
I'm not talking about your link. The whole point of those schools is to take them away from their own communities and culture and assimilate them. It's a form of colonialism and the PRC is an empire.
In both cases, they still learn their respective language in parallel to Mandarin, which is the national language. So I don't understand how this is evil or smth.