The keyboard is not very good at determining which words I'm internally vocalizing either, still seems to work.
The point I'm trying to convey is that maybe we can learn to transmit words using some form of brain reader, but that measures something else than vocalizing.
It is possible today to make EEG controlled devices. They typically differentiate between a small number of real or imagined movements in the user. This is awesome, because it can allow severely paralyzed people to communicate, control a wheelchair. etc. Nevertheless, the algorithms used to do this are perfectly useless when it comes to distinguishing whatever words the user is internally vocalizing.