vocal tract

noun2

1. •
   (anatomy) Portion of the human body where speech sounds are articulated.

   • ...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. — 2001
2. •
   Portion of a bird's anatomy that filters or modifies sound; the syrinx, oral cavity, and beak, plus portions of the esophagus and trachea.

   • Beak motions are not necessarily the only means by which birds might vary the acoustic properties of the vocal tract. — 1998