I think language allows for "higher level" consciousness, higher level thought, which is why humans are generally considered the most intelligent animal. Langauge allows us to form more complicated structures, especially written language, it allows us to organize large scale endeavors, like society, and society builds the notion of consciousness. But language, at least human language is obviously not necessary for consciousness, or at least it's obvious to anyone who has a dog.
Our brains are wired for consciousness, not language. That's why it's still possible for deaf/mute people to be part of society... they are just as "conscious" as anyone else.