To get in I would say not as really the USA does not have an official language. But I do think they should all be required to take a class which I believe they do in order to be a citizen.
I think they should have a basic knowledge of English. I've come across some people who have been here twenty years or more and have made no effort to learn, it's easy to live in communities with other people of the same nationality but people can't integrate into society if they don't want to learn the language.
I think anyone that wants to live here should know the language. There are other countries that require a working knowledge of their language so why not the US.