Lateral consonant

A lateral is an L-like consonant, in which the airstream proceeds along the sides of the tongue, but is blocked by the tongue from going through the middle of the mouth.

Most commonly, the tip of the tongue makes contact with the upper teeth (see dental consonant) or the upper gum (the alveolar ridge) just behind the teeth (see alveolar consonant). The most common laterals are approximants and belong to the class of liquids, though lateral fricatives and affricates are common in some parts of the world.

The labiodental fricatives often—perhaps usually—have lateral airflow, as the lip blocks the airflow in the center, but they are nonetheless not considered lateral consonants because no language makes a distinction between the two possibilities. Plosives are never lateral—although they may have lateral release—and the distinction is meaningless for nasals and for consonants articulated in the throat.

Consonants are not necessarily lateral or central. Some, such as Japanese r, are not defined by centrality; Japanese r varies between a central flap and a lateral flap.

Examples
English has one lateral phoneme: the lateral approximant, which in many accents has two allophones. One, found before vowels as in lady or fly, is called clear l, pronounced as the alveolar lateral approximant with a "neutral" position of the body of the tongue. The other variant, so-called dark l found before consonants or word-finally, as in bold or tell, is pronounced as the velarized alveolar lateral approximant with the tongue assuming a spoon-like shape with its back part raised, which gives the sound a - or -like resonance. In some languages, like Albanian, those two sounds are different phonemes. East Slavic languages contrast and  but do not have [l].

In many British accents (e.g. Cockney), dark may undergo vocalization through the reduction and loss of contact between the tip of the tongue and the alveolar ridge, becoming a rounded back vowel or glide. This process turns tell into something like. A similar process happened during the development of many languages, including Brazilian Portuguese, Old French, and Polish, in all three of these resulting in or, whence Modern French sauce as compared with Spanish salsa, or Polish Wisła (pronounced ) as compared with English Vistula.

In central and Venice dialects of Vèneto, intervocalic has turned into a semivocalic, so that the written word ła bała is pronounced. The orthography uses the letter ł to represent this phoneme (note that it doesn't specifically represent the [e̯] sound, it represents the phoneme which in some dialects is [e̯] and in some [l]).

Many aboriginal Australian languages have a series of three or four lateral approximants, as do various dialects of Irish. Rarer lateral consonants include the retroflex laterals that can be found in many Languages of India and in some Swedish dialects, and the voiceless alveolar lateral fricative, found in many Native North American languages, Welsh and Zulu. In Adyghe and some Athabaskan languages like Hän, both voiceless and voiced alveolar lateral fricatives occur, but there is no approximant. Many of these languages also have lateral affricates. Some languages have palatal or velar voiceless lateral fricatives or affricates, such as Dahalo and Zulu, but the IPA has no symbols for these sounds. However, appropriate symbols are easy to make by adding a lateral-fricative belt to the symbol for the corresponding lateral approximant (see below). Failing that, a devoicing diacritic is added to the approximant.

Nearly all languages with such lateral obstruents also have the approximant. However, there are a number of exceptions, many of them located in the Pacific Northwest area. For example, Tlingit has but no. Other examples from the same area include Nuu-chah-nulth and Kutenai, and elsewhere, Chukchi and Kabardian.

Standard Tibetan has a voiceless lateral approximant, usually romanized as lh, as in the name Lhasa.

Pashto has a retroflex lateral flap.

There are a large number of lateral click consonants; seventeen occur in !Xóõ.

Lateral trills are possible (but occur in no known language). It is also possible to articulate uvular and pharyngeal or epiglottal laterals. Uvular lateral approximant has been reported to occur in some speakers of American English.

Approximants

 * Voiceless alveolar lateral approximant
 * Voiced alveolar lateral approximant
 * Retroflex lateral approximant
 * Voiceless palatal lateral approximant
 * Voiced palatal lateral approximant
 * Velar lateral approximant

Fricatives

 * Voiceless alveolar lateral fricative (in Navajo, Welsh)
 * Voiced alveolar lateral fricative (in Mongolian, Tigak)
 * Voiceless retroflex lateral fricative (or [] ) (in Toda)
 * Voiceless palatal lateral fricative (or [] ) (in Dahalo)
 * Voiced velar lateral fricative (in Archi)
 * Voiceless velar lateral fricative (or [] ) (in Archi, Nii)

Affricates

 * Voiceless alveolar lateral affricate (in Navajo)
 * Ejective alveolar lateral affricate (in Navajo)
 * Voiced alveolar lateral affricate
 * Voiceless palatal lateral affricate (or [c] ) (in Hadza)
 * Ejective palatal lateral affricate (or [cʼ] ) (in Dahalo, Hadza)
 * Voiced velar lateral affricate (in Laghuu)
 * Voiceless velar lateral affricate (or [k] ) (in Archi, and Laghuu)
 * Ejective velar lateral affricate (or [kʼ] ) (in Archi, Gǀwi, Zulu)

Flaps

 * Alveolar lateral flap (in Wayuu)
 * Retroflex lateral flap (or [] ) (in Pashto, Iwaidja)
 * Palatal lateral flap (in Iwaidja)

Ejective

 * Alveolar lateral ejective fricative (in Adyghe)
 * Alveolar lateral ejective affricate
 * Palatal lateral ejective affricate
 * Velar lateral ejective affricate

Clicks

 * Dental lateral clicks, , , etc. (in Juu)
 * Alveolar lateral clicks, , , etc. (in Khoisan and Bantu)

Other symbols
The symbol for the voiceless alveolar lateral fricative forms the basis for the occasional ad hoc symbols for other voiceless lateral fricatives—retroflex, palatal, and velar (the latter two only known from affricates):



The symbol for the alveolar lateral flap is the basis for the expected symbol for the retroflex lateral flap:



Such symbols are rare, but are becoming more common now that font-editing software has become accessible. The letter for the voiceless retroflex lateral fricative was included in Unicode 6.0 as, with the annotation, voiceless lateral retroflex fricative, used to transcribe Toda. Everson Mono has a glyph for this code point. Note however that this is not sanctioned by the IPA. There are no Unicode code points assigned for the other letters, except that " with belt" and " with retroflex hook" can be represented as composite characters ( or, followed by ). Also note that although the Charis SIL and Doulos SIL fonts have those glyphs in the Private Use Areas (PUA), PUA code points should not be used for data exchange.