“You wouldn’t need to talk,” Musk said, adding: “We could still do it for sentimental reasons.”
He went on: “You would be able to communicate very quickly and with far more precision … I’m not sure what would happen to language. In a situation like this it would kind of be like The Matrix. You wanna speak in a different language? No problem, just download the program.”
Asked how long it would take for his firm to develop technology advanced enough to do it, Musk said between five and 10 years, “if the development continues to accelerate”.
I've talked about that sort of thing in an old post, Why we'll never be able to build technology for Direct Brain-to-Brain Communication. This link will take you to a number of posts about technology for brain-to-brain communication; Musk is hardly the only one working on it.