So they're saying the cause/purpose of consciousness is to reduce all the input data into a way to communicate with other humans via speech? Weird. That also makes the strange assumption that only humans, or beings that need to communicate, would have consciousness.

It seems fairly reasonable to suppose that any organism with sensory inputs that can act independently (perceive its environment and interact with it) would have to have some kind of consciousness to operate through. IOW to interpret the input signals and form a kind of mental model out of them. Regardless of how simple or complex that consciousness may be or whether communication might be involved.