My girlfriend asked me once in a Restaurant (Cafe Norden in Kopenhagen) why I was ordering in English. Then, I spent the complete evening ordering everything in Danish, to always receive answers in English. And this nearly everywhere (not my bakery, the girls there could not speak a word of English, this was an exception). This was in the early 2000's. This never happened to me in all the other countries I have been living in. A Danish colleague simply told me that he does not like to listen to broken Danish, better switch to English.
Still have a lot of friends in Denmark, integration there is not easy, even for highly qualified people from the EU.
You can look at any country in western europe to see how it's not.
[1] https://www.pure.ed.ac.uk/ws/portalfiles/portal/35314239/sre...
In the US, Italians, Irish, and Germans, as just a few examples, all were treated as unassmilated aliens. People say the same things, generation after generation about newcomers. If you moved to a country with a different language and culture, you might make an effort to learn the language but you would still think, read, etc. in your native language. Your kids would know both languages; their kids would of course speak the language of their surroundings.
What solves these problems is a fundamental belief in freedom for all. People don't need to speak your language to be your equal and be just as human, with the same rights as you.
Here's Benjamin Franklin (Palatine refers to the Holy Roman Empire or Germanic regions, depending on the source):
"[W]hy should the Palatine Boors be suffered to swarm into our Settlements, and by herding together establish their Language and Manners to the Exclusion of ours? Why should Pennsylvania, founded by the English, become a Colony of Aliens, who will shortly be so numerous as to Germanize us instead of our Anglifying them, and will never adopt our Language or Customs, any more than they can acquire our Complexion.
Which leads me to add one Remark: That the Number of purely white People in the World is proportionably very small. All Africa is black or tawny. Asia chiefly tawny. America (exclusive of the new Comers) wholly so. And in Europe, the Spaniards, Italians, French, Russians and Swedes, are generally of what we call a swarthy Complexion; as are the Germans also, the Saxons only excepted, who with the English, make the principal Body of White People on the Face of the Earth. I could wish their Numbers were increased. And while we are, as I may call it, Scouring our Planet, by clearing America of Woods, and so making this Side of our Globe reflect a brighter Light to the Eyes of Inhabitants in Mars or Venus, why should we in the Sight of Superior Beings, darken its People? why increase the Sons of Africa, by Planting them in America, where we have so fair an Opportunity, by excluding all Blacks and Tawneys, of increasing the lovely White and Red? But perhaps I am partial to the Complexion of my Country, for such Kind of Partiality is natural to Mankind."
https://www.theatlantic.com/politics/archive/2008/02/swarthy...