 Consonant

A consonant is a speech sound articulated with a closure or constriction that significantly shapes or interrupts airflow. Its physical description typically specifies place of articulation, manner of articulation and voicing. These describe where the articulators act, how the air passes and whether the vocal folds vibrate.^[ref]

The sounds [p] and [b] both involve the lips and a closure, but differ in their usual voicing classification. A sustained [m] also closes the lips, while opening a route through the nose: an oral closure does not imply that all airflow stops. The distinction between a plosive and a nasal consonant therefore depends on airflow paths, not merely the fact that two lips touch.

The category concerns speech sounds, rather than letters: a written symbol's name and its sound in a particular word are different objects of study. A consonant can also function as a syllabic consonant, so a syllable nucleus is not invariably a vowel.