approximant

Approximants are speech sounds (phones) that could be regarded as intermediate between vowels and "typical" consonants. In the articulation of approximants, articulatory organs produce a narrowing of the vocal tract, but leave enough space for air to flow without much audible turbulence. Approximants are therefore more open than fricatives. This class of sounds includes lateral approximants like [l], as in lip, and approximants like [j] and [w] in yes and well which correspond closely to vowels and semivowels.

Corresponding vowels

Some approximants resemble vowels. The term semivowel is often used for such segments. (Semivowels are non-syllabic vowel-like segments. While some phoneticians restrict the term to true non-syllabic vowels, which form diphthongs, others include the subset of approximants that resemble vowels. The difference phonetically is that these approximants are closer than the corresponding non-syllabic vowels.)

In articulation and often diachronically, palatal approximants correspond to front vowels, velar approximants to back vowels, and labialized approximants to rounded vowels. In American English, the rhotic approximant corresponds to the rhotic vowel.

Approximant	Corresponding vowel	Place of articulation
β̞	ʉ	Labial
j	i	Palatal
ɥ	y	Labiopalatal
ɰ	ɯ	Velar
w	u	Labiovelar
ɹ	ɝ	Central rhotic
ɻ	ɚ	Retroflex
ʕ̞	ɑ	Pharyngeal
ʕ̞ʷ	ɒ	Labiopharyngeal

Approximants versus fricatives

When emphasized, approximants may be slightly fricated (that is, the airstream may become slightly turbulent), which is reminiscent of fricatives. Examples are the y of English yes! (especially when lengthened) and the "weak" allophones of Spanish b, d, g, which are often transcribed as fricatives (often due perhaps to a lack of dedicated approximant symbols). However, such frication is generally slight and intermittent, unlike the strong turbulence of fricative consonants.

This confusion is also common with voiceless approximants, which necessarily have a certain amount of fricative-like noise. For example, the voiceless labialized velar approximant [ʍ] has traditionally been called a fricative, and no language is known to contrast it with a voiceless labialized velar fricative [xʷ]. Tibetan has a voiceless lateral approximant, [l̥], and Welsh has a voiceless lateral fricative [ɬ], but the distinction is not always clear from descriptions of these languages. Again, no language is known to contrast the two.^[1]

For places of articulation further back in the mouth, languages do not contrast voiced fricatives and approximants. Therefore the IPA allows the symbols for the voiced fricatives to double for the central approximants, with or without a lowering diacritic.

Occasionally the glottal "fricatives" are called approximants, since [h] typically has no more frication than voiceless approximants, but they are often phonations of the glottis without any accompanying manner or place of articulation.

Central approximants

• bilabial approximant [β̞] (a consonantal [ʉ]; usually written <β>)
• labiodental approximant [ʋ]
• dental approximant [ð̞] (usually written <ð>)
• alveolar approximant [ɹ]
• retroflex approximant [ɻ] (a consonantal [ɚ])
• palatal approximant [j] (a consonantal [i])
• velar approximant [ɰ] (a consonantal [ɯ])
• uvular approximant [ʁ̞] (usually written <ʁ>)
• pharyngeal approximant [ʕ̞] (a consonantal [ɑ]; usually written <ʕ>)
• epiglottal approximant [ʢ̞] (usually written <ʢ>)

Lateral approximants

In lateral approximants, the center of tongue makes solid contact with the roof of the mouth. However, the defining location is the side of the tongue, which only approaches the teeth.

• voiced alveolar lateral approximant [l]
• voiceless alveolar lateral approximant [l̥]
• retroflex lateral approximant [ɭ]
• palatal lateral approximant [ʎ]
• velar lateral approximant [ʟ]

Coarticulated approximants with dedicated IPA symbols

• voiced labialized velar approximant [w] (a consonantal [u])
• voiceless labialized velar approximant [ʍ]
• labialized palatal approximant [ɥ] (a consonantal [y])
• velarized alveolar lateral approximant [ɫ]

A "central" approximant?

Although many languages have central vowels [ɨ, ʉ] which lie between back/velar [ɯ, u] and front/palatal [i, y], there are no confirmed reports of corresponding approximants. However, Mapudungun may be a possibility: It has three high vowel sounds, /i/, /u/, /ɨ/, written "i", "u", "ü", and three corresponding consonants, written "y", "w", "q". The first two are clearly /j/ and /w/. The "q" is often described as a voiced unrounded velar fricative, but some texts note a correspondence between "q" and /ɨ/ that is parallel to /j/-/i/ and /w/-/u/. An example is liq /ˈliɣ/ ([ˈliɉ]?) "white".^[2]

References

See also

Look up approximant in Wiktionary, the free dictionary.

• List of phonetics topics
• Semivowel