Vocal Tract

The vocal tract is the air passage extending from the larynx upward to the lips and nostrils, comprising the resonating cavities and articulators that shape the airstream into speech. It is the primary object of Articulatory Phonetics.

The three cavities

Above the larynx the tract divides into three resonating cavities. The pharyngeal cavity sits between the larynx and the back of the oral cavity. The oral cavity runs from the pharynx forward to the lips. The nasal cavity lies above the soft palate and exits at the nostrils; it is coupled to or sealed off from the oral tract by the velum. When the velum is raised, airflow exits through the mouth alone (oral sounds); when it is lowered, airflow also passes through the nose, producing nasal consonants such as /m, n, ŋ/ and nasalised vowels.

Articulators

The articulators are the structures that shape the cavity. The lower lip and tongue are the principal active articulators — they move toward target locations. The passive articulators include the upper lip, the upper teeth, the alveolar ridge behind the upper teeth, the hard palate, the soft palate (velum), the uvula, and the back wall of the pharynx. The tongue itself is conventionally divided into tip, blade, front, back, and root, each capable of independent movement and corresponding to different places of articulation.

Source and filter

The vocal tract is the filter in the source–filter model of speech production. The larynx, with vocal-fold vibration generating periodic phonation, supplies the source. The cavity above the glottis acts as a resonator whose shape determines which frequencies are amplified, producing the formant patterns that distinguish vowels and shape consonants.

Cross-linguistic and ELT relevance

All human languages exploit the same vocal-tract anatomy, but each selects a particular subset of articulator configurations as phonemic. Naming the parts gives pronunciation teachers a precise vocabulary — touch the alveolar ridge with the tongue tip, lower the velum — that turns vague imitation into targeted instruction.

References

• Ladefoged, P., & Johnson, K. (2014). A Course in Phonetics (7th ed.). Cengage Learning.
• Roach, P. (2009). English Phonetics and Phonology: A Practical Course (4th ed.). Cambridge University Press.
• Cruttenden, A. (2014). Gimson's Pronunciation of English (8th ed.). Routledge.