Spectrographic Speech Patterns of Identical Twins
L. G. Kersta, J. A. Colangelo · The Journal of the Acoustical Society of America · 1970
It has previously been reported that speakers are identifiable on the basis of a voiceprint or spectrographic analyses of their voices. This study applies the same techniques to the voices of identical twins to demonstrate that there are invariant qualities of the voice that are unique to the individual even when vocal-tract physiology may be expected to be identical and when environmental effects have familial similarities. The tests were first performed by two scientifically näive high school girls whose training consisted initially of voiceprint matching of unrelated individuals, followed by matching tasks on thirty pairs of fraternal twins. In the testing procedure, the panel was presented with two spectrograms of one pair of identical twins. Each twin had uttered a phrase containing the words “were you.” The panel was then presented with a third spectrogram containing the words “you were” and asked which of the first two speakers was the same as the third. In 60 attempts, they were able to correctly identify 52 of the twins based on two words spoken in common. The tests were then repeated using a more skilled technician, who successfully identified 59 of the 60 speakers.