Forced? No - nobody has that right. Apart from that it's even harder if you think about how that would even be enforced... do they have to know the language BEFORE moving? What if it isn't taught where they're from? In the case of countries or provinces that have two native languages what then? If you're being forced after they move, how is that done? Knowledge isn't immediately transfered, you can't actually force people to learn. Would you kick them out after a certain amount of time if they hadn't managed it? What if economical or intellectual or health factors played a part in preventing them? What's the opinion on sign languages? I do think people can be better involved in the communities they move into if they know or are learning the language and establishing better and more affordable education centres and services would seriously aid that, but it's not something you could (in what i would think is a fair and just world, but okay i can think of ways) or should ever force on migrants.