Summary

Consonants are a major class of sounds occurring in all human languages. Typologically, consonant inventories are richer than vowel inventories. Consonants have been classified according to four basic features. Airstream mechanism is one of these features and describes the direction of airflow in or out of the oral cavity. The outgoing airflow is further separated according to its origin, that is, air coming from the lungs (pulmonic) or the oral cavity (non-pulmonic). Consonants are also grouped according to their phonological voicing contrast, which can be manifested phonetically by the presence or absence of vocal fold oscillations during the oral closure/constriction phase and by the duration from an oral closure release to the onset of voicing. Place of articulation is the third feature and refers to the location at which a consonantal constriction or closure is produced in the vocal tract. Finally, manner of articulation reflects different timing and coordinated actions of the articulators closely tied to aerodynamic properties.