DARPA is working on Advanced Speech Encoding, aimed at replacing microphones with non-acoustic sensors that detect speech via the speaker’s nerve and muscle activity, rather than sound itself.

DARPA is also pursuing an approach first developed at NASA’s Ames lab, which involves placing electrodes called electromyographic sensors on the neck, to detect changes in impedance during speech. A neural network processes the data and identifies the pattern of words. The sensor can even detect subvocal or silent speech. The speech pattern is sent to a computerised voice generator that recreates the speaker’s words.

The development was predicted in David Brin’s 1989 novel, EARTH. – Ed.