Consonant

A consonant is a sound in spoken language that is characterized by a closure or stricture of the vocal tract sufficient to cause audible turbulence. The word consonant comes from Latin and means "sounding with" or "sounding together", the idea being that consonants don't sound on their own, but only occur with a nearby vowel, which is the case in Latin. This conception of consonants, however, does not reflect the modern linguistic understanding which defines consonants in terms of vocal tract constriction.

Since the number of consonants in the world's languages is much greater than the number of consonant letters in any one alphabet, linguists have devised systems such as the International Phonetic Alphabet (IPA) to assign a unique symbol to each possible consonant. In fact, the Latin alphabet, which is used to write English, has fewer consonant letters than English has consonant sounds, so some letters represent more than one consonant, and digraphs like "sh" and "th" are used to represent some sounds. Many speakers aren't even aware that the "th" sound in "this" is a different sound from the "th" sound in "thing" (in the IPA they're [&#240;] and [&#952;], respectively).

Each consonant can be distinguished by several features:
 * The manner of articulation is the method that the consonant is articulated, such as nasal (through the nose), stop (complete obstruction of air), or approximant (vowel like).
 * The place of articulation is where in the vocal tract the obstruction of the consonant occurs, and which speech organs are involved. Places include bilabial (both lips), alveolar (tongue against the gum ridge), and velar (tongue against soft palate). Additionally, there may be a simultaneous narrowing at another place of articulation, such as palatalisation or pharyngealisation.
 * The phonation of a consonant is how the vocal cords vibrate during the articulation. When the vocal cords vibrate fully, the consonant is called voiced; when they do not vibrate at all, it's voiceless.
 * The voice onset time (VOT) indicates the timing of the phonation. Aspiration is a feature of VOT.
 * The airstream mechanism is how the air moving through the vocal tract is powered. Most languages have exclusively pulmonic egressive consonants, which use the lungs and diaphragm, but ejectives, clicks, and implosives use different mechanisms.
 * The length is how long the obstruction of a consonant lasts. This feature is not distinctive in English, but various languages such as Italian, Japanese and Finnish have two length levels, "single" and "geminate". Estonian and some Sami languages have three lengths on the phonetic level: short, geminate, and long geminate.
 * The articulatory force is how much muscular energy is involved. This has been proposed many times, but no distinction relying exclusively on force has ever been demonstrated.

All English consonants can be classified by a combination of these features, such as "voiceless alveolar stop consonant" [t]. In this case the airstream mechanism is omitted.

Some pairs of consonants like p::b, t::d are sometimes called fortis and lenis, but this is a phonological rather than phonetic distinction.

Consonant as a symbol
The word consonant is also used to refer to a letter of an alphabet that denotes a consonant sound. Consonant letters in the English alphabet are B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, W, X, Z, and usually Y: The letter Y stands for the consonant [j] in "yoke" but for the vowel in "myth", for example.