@wis75 your point about Europe is really important. Where multilingualism is compelled, there will be outlets and support for speaking multiple languages, translation, etc… Since the EU (and places like Switzerland) legally mandate multilingualism, there is a “market” for speaking multiple languages. My city in the US is extremely multilingual and, in my old neighborhood, I could have spoken French every day, along with Spanish and Creole. Without a mandate making it so that public discourse needs to be multilingual, it’s very hard to create a market for it, though.