Laterals are "L"-like consonants pronounced with an occlusion made somewhere along the axis of the tongue, while air from the lungs escapes at one side or both sides of the tongue.
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.
English has one lateral phoneme: the lateral approximant /l/, 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 [l] 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 [ɫ] with the tongue assuming a spoon-like shape with its back part raised, which gives the sound a [w]- or [ʟ]-like resonance. In some languages, like Albanian, those two sounds are different phonemes. East Slavic languages contrast [ɫ] and [lʲ] but do not have a plain [l].
In many British accents (e.g. London English), dark [ɫ] may undergo vocalization through the reduction and loss of contact between the tip of the tongue the alveolar ridge, becoming a rounded back vowel or glide. This process turns tell into something like [tɛ[[ɰ]]. A similar process happened in Brazilian Portuguese and in Old French, resulting in [w], whence Modern French sauce as compared with Spanish salsa. Also in Polish historical [ɫ] (spelled ł ) has become [w] even word-initially or between vowels.
In central and Venice dialects of Vèneto intervocalic /l/ has turned into a semivocalic [e], so that the written word la bala is pronounced [abae̯a].
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 most Indic languages and in some Swedish dialects; and the sound of Welsh ll, the voiceless alveolar lateral fricative /ɬ/ that is also found in Zulu and many Semitic and Native American languages. In Adyghe and some Athapaskan languages like Hän both voiceless and voiced alveolar lateral fricative 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, Tlingit is an exception, with but no /l/.
The symbol for the voiceless alveolar lateral fricative forms the basis for the occasional ad hoc symbols for other voiceless lateral fricatives: retroflex, palatal, 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. Note however that since they are not sanctioned by the IPA, there are no Unicode values for them.