There is a narrow class of uses of language where you intend to communicate. Communication refers to an effort to get people to understand what one means. And that, certainly, is one use of language and a social use of it. But i don't think it is the only social use of language. Nor are social uses the only uses of language.
It is a mass language only in the same sense that its baseball slang is born of baseball players. That is, it is a language which is being molded by writers to do delicate things and yet be within the grasp of superficially educated people. It is not a natural growth, much as its proletarian writers would like to think so. But compared with it at its best, english has reached the alexandrian stage of formalism and decay.
I think the use of language is a very important means by which this species, because of its biological nature, creates a kind of social space, to place itself in interactions with other people. It doesn't have much to do with communication in a narrow sense; that is, it doesn't involve transmission of information. There is much information transmitted but it is not the content of what is said that is transmitted.