How parrots talk: insights based on CT scans, image processing, and mathematical models

  title={How parrots talk: insights based on CT scans, image processing, and mathematical models},
  author={Dianne K. Patterson and Irene M. Pepperberg and Brad H. Story and Eric A. Hoffman},
  booktitle={Medical Imaging},
Little is known about mechanisms of speech production in parrots. Recently, however, techniques for correlating vocal tract shape with vowel production in humans have become more sophisticated and we have adapted these techniques for use with parrots. We scanned two grey parrot heads with intact vocal tracts. One specimen, 'Oldbird' was fixed with its beak propped open; the second 'Youngbird' was fixed with its beak closed. Using VIDA software, we (1) established that differences in tongue and… 

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Bird voices and resonant tuning in helium-air mixtures,

  • Ph.D. Thesis, Univ. California,
  • 1966

Pepperberg, "A comparative study ofhuman and parrot phonation: Acoustic and articulatory correlates

  • ofvowels," J. Acoust. Soc. Amer
  • 1994

Some biological constraints on the analysis ofprosody." Signal to Syntax: Bootstrappingfrom Speech to Grammar in EarlyAcquisition

  • 1996

Greenewalt, BirdSong: Acoustics andPhysiology

  • 1968

Mechanisms of American English vowel production in an African Grey parrot