vocal tract

Compound of vocal +‎ tract.

vocal tract (plural vocal tracts)

1. (phonetics) Portion of the human body where speech sounds are articulated; the oral cavity, nasal cavity, and pharynx.
   • 2001, Michael Dobrovolsky, “Phonetics: The Sounds of Language”, in William O'Grady, John Archibald, Mark Aronoff, and Janie Rees-Miller, editors, Contemporary Linguistics, →ISBN, page 18:

     ...the tube of the throat between the larynx and the oral cavity, which is called the pharynx; the oral cavity; and the nasal cavity. These passages are collectively known as the vocal tract.

2. (ornithology) Portion of a bird's anatomy that filters or modifies sound; the syrinx, oral cavity, and beak, plus portions of the esophagus and trachea.
   • 1998, Abbot Gaunt and Stephen Nowicki, “Sound Production in Birds: Acoustics and Physiology Revisited”, in Steven Hopp, Michael Owren, and Christopher Evans, editors, Animal Acoustic Communication: Sound Analysis and Research Methods, →ISBN, page 308:

     Beak motions are not necessarily the only means by which birds might vary the acoustic properties of the vocal tract.