"I understand that you are sensitive about the issue of assimilation," Erdogan says. "No one can demand that from you."
I will make only one comment on that since we have the same problem here.
If they aren't happy, if they don't want to learn the language and if they don't want to live like the others country citizens the solution is easy : they Just had go back to their country if it is so great why quit it...
I don't know but if I quit my country for one reason or another I will try my best to learn the language and the custom of the new one. This is just a question of respect for a country that had no obligation to welcome you at all.