Audeo has just demonstrated their nifty subvocal speech input device in a new context; a neckband that translates thought into speech by interpreting signals sent from the brain to the vocal chords. Technovelgy readers are already familiar with the idea; Audeo used it in their Thinking Man's Wheelchair demonstrated last September.
(Michael Callahan talking on the phone)
The device does not provide unlimited translation; it is able to respond with about 150 basic words and phrases. It is anticipated that the device will offer unlimited vocabulary by the end of the year, through recognition of speech phonemes.
(Audeo voiceless communication demo video)
I'm pretty sure I've seen earlier references to this idea; I think that Clint Eastwood used something similar to this in the 1982 movie Firefox. The Firefox was an advanced Russian military plane that had a thought-guided weapons system. He subvocalized in Russian, natch.
David Brin wrote about it more specifically in his 1990 novel Earth.
She took a subvocal input device from its rack and placed the attached sensors on her throat, jaw, and temples. A faint glitter in the display screens meant the machine was already tracking her eyes, noting by curvature of lens and angle of pupil the exact spot on which she focused at any moment.
She didn't have to speak aloud, only intend to. The subvocal read nerve signals, letting her enter words by just beginning to will them...
(Read more about the Subvocal Input Device)
These two references to the idea of subvocal communication are the earliest that I know about; I couldn't find anything earlier in other fields, but I'm betting that this idea has been around for a while. Anyone?
This technology could also make the involuntary participation in the cell phone calls of a million strangers obsolete. We may not need the hush-a-phone after all.