"Contactees" commonly report that aliens "talked to them inside their heads," meaning they communicated with them telepathically. Often these people communicate with them right back, the same way, and a whole conversation takes place inside two heads. Soon, human-to-human speech may be the same way.
When you read or think, you usually "say" the words to yourself, inside your head. What if someone could "read" this? It would be like a musician watching someone play the piano on TV while the "mute" button is on--In New Scientist, Helen Thomson quotes neuroscientist Brian Pasley as saying, "If a pianist were watching a piano being played on TV with the sound off, they would still be able to work out what the music sounded like because they know what key plays what note."
In order to figure out what aspects of speech are related to what kind of brain activity, his research team spoke words and sentences to people and watched what parts of their brains "lit up."
Sound is made up of different frequencies which are processed in different parts of the brain. Thomson quotes Pasley as saying,. "One spot (of neurons) might only care about a frequency range of 1000 hertz and doesn't care about anything else. Another spot might care about a frequency of 5000 hertz." But other parts of audible speech need to be analyzed as well. Computer analysis helped pull all these aspects together, plot the sounds as a radio wave, and decode them. When the researchers replayed the waves, they recreated the speech--in a crude way, but it's a beginning.
Thomson quotes him as saying, "We don't know if speech from thoughts is possible yet. It's certainly the hope."
When Whitley published Communion (now he's published the sequel), the Striebers received what they estimate to be a quarter of a million letters from other contactees--and Anne Strieber read them all. This makes her a "walking encyclopedia" of what REALLY HAPPENS to people during Visitor experiences, so her interviews with contactees are very special--and if you're a subscriber, you can listen to them all.