Consider the millions of German Americans, many of whom settled the Midwest still posting billboards and business signs in public, in Deutsch today. Many Spanish speakers are not assimilating because of the sheer size of their local communities. I submit the Spanish speakers clinging to their language will be screwing themselves, and limiting their growth and freedom of effortless societal movement.Regarding language issues that threaten societies, see Canada.
Today, everyone I know whose native language is spanish also speaks fluent English. There are many more bilingual native Spanish speaker than there are native English speakers. There is even a problem with immigrants who know only English and regret that they are not fluent in Spanish. Fifty years from now it may be importaant to speak both Spanish and English if you live in this country. It looks as if Spanish speakers already have a leg up since they are more likely to be bilingual. Eventually, the languages may fuse and the result will be something that is unrecognizable as is English of the 11th century. I don't know much about Canada's problems, but I do know that Quebec is my favorite province.