What is "vocal tube"

Vocal \Vo"cal\ (v[=o]"kal), a. [L. vocalis, fr. vox, vocis, voice: cf. F. vocal. See Voice, and cf. Vowel.]

1. Of or pertaining to the voice or speech; having voice; endowed with utterance; full of voice, or voices.

   To hill or valley, fountain, or fresh shade, Made vocal by my song.
   --Milton.

2. Uttered or modulated by the voice; oral; as, vocal melody; vocal prayer. ``Vocal worship.''
   --Milton.

3. Of or pertaining to a vowel or voice sound; also, spoken with tone, intonation, and resonance; sonant; sonorous; -- said of certain articulate sounds.

4. (Phon.) (a) Consisting of, or characterized by, voice, or tone produced in the larynx, which may be modified, either by resonance, as in the case of the vowels, or by obstructive action, as in certain consonants, such as v, l, etc., or by both, as in the nasals m, n, ng; sonant; intonated; voiced. See Voice, and Vowel, also Guide to Pronunciation, [sect][sect] 199-202. (b) Of or pertaining to a vowel; having the character of a vowel; vowel. Vocal cords or Vocal chords. n. pl. (Anat.) The two pairs of mucous membranes that project into the larynx, and which produce the sounds of speech by vibrating under the influence of air exhaled from the lungs. See Larynx, and the Note under Voice, n.,

   1. Vocal fremitus [L. fremitus a dull roaring or murmuring] (Med.), the perceptible vibration of the chest wall, produced by the transmission of the sonorous vibrations during the act of using the voice.

      Vocal music, music made by the voice, in distinction from instrumental music; hence, music or tunes set to words, to be performed by the human voice.

      Vocal tube (Anat.), the part of the air passages above the inferior ligaments of the larynx, including the passages through the nose and mouth.