Approximant consonant


Approximants are speech sounds that involve the articulators approaching each other but not narrowly enough nor with enough articulatory precision to create turbulent airflow. Therefore, approximants fall between fricatives, which do produce a turbulent airstream, and vowels, which produce no turbulence. This class is composed of sounds like and semivowels like and , as well as lateral approximants like .

Terminology

Before Peter Ladefoged coined the term "approximant" in the 1960s, the term "frictionless continuant" referred to non-lateral approximants.
In phonology, "approximant" is also a distinctive feature that encompasses all sonorants except nasals, including vowels, taps and trills.

Semivowels

Some approximants resemble vowels in acoustic and articulatory properties and the terms semivowel and glide are often used for these non-syllabic vowel-like segments. The correlation between semivowels and vowels is strong enough that cross-language differences between semivowels correspond with the differences between their related vowels.
Vowels and their corresponding semivowels alternate in many languages depending on the phonological environment, or for grammatical reasons, as is the case with Indo-European ablaut. Similarly, languages often avoid configurations where a semivowel precedes its corresponding vowel. A number of phoneticians distinguish between semivowels and approximants by their location in a syllable. Although he uses the terms interchangeably, remarks that, for example, the final glides of English par and buy differ from French par and baille in that, in the latter pair, the approximants appear in the syllable coda, whereas, in the former, they appear in the syllable nucleus. This means that opaque contrasts can occur in languages like Italian and Spanish.
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. This can create alternations.
In addition to alternations, glides can be inserted to the left or the right of their corresponding vowels when they occur next to a hiatus. For example, in Ukrainian, medial triggers the formation of an inserted that acts as a syllable onset so that when the affix is added to футбол to make футболіст 'football player', it is pronounced, but маоїст, with the same affix, is pronounced with a glide. Dutch for many speakers has a similar process that extends to mid vowels:
Similarly, vowels can be inserted next to their corresponding glide in certain phonetic environments. Sievers' law describes this behaviour for Germanic.
Non-high semivowels also occur. In colloquial Nepali speech, a process of glide-formation occurs, where one of two adjacent vowels becomes non-syllabic; the process includes mid vowels so that features a non-syllabic mid vowel. Spanish features a similar process and even nonsyllabic can occur so that ahorita is pronounced. It is not often clear, however, whether such sequences involve a semivowel or a diphthong, and in many cases, it may not be a meaningful distinction.
Although many languages have central vowels, which lie between back/velar and front/palatal, there are few cases of a corresponding approximant. One is in the Korean diphthong or though it is more frequently analyzed as velar, and Mapudungun may be another, with three high vowel sounds,,, and three corresponding consonants,, and, and a third one is often described as a voiced unrounded velar fricative; some texts note a correspondence between this approximant and that is parallel to – and –. An example is liq .

Approximants versus fricatives

In addition to less turbulence, approximants also differ from fricatives in the precision required to produce them. When emphasized, approximants may be slightly fricated, which is reminiscent of fricatives. For example, the Spanish word ayuda features a palatal approximant that is pronounced as a fricative in emphatic speech. Spanish can be analyzed as having a meaningful distinction between fricative, approximant, and intermediate. However, such frication is generally slight and intermittent, unlike the strong turbulence of fricative consonants.
Because voicelessness has comparatively reduced resistance to air flow from the lungs, the increased air flow creates more turbulence, making acoustic distinctions between voiceless approximants and voiceless fricatives difficult. This is why, for example, no language is known to contrast the voiceless labialized velar approximant with a voiceless labialized velar fricative. Similarly, Standard Tibetan has a voiceless lateral approximant,, and Welsh has a voiceless lateral fricative, but the distinction is not always clear from descriptions of these languages. Again, no language is known to contrast the two. Iaai is reported to have an unusually large number of voiceless approximants, with.
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 approximants, with or without a lowering diacritic.
Occasionally, the glottal "fricatives" are called approximants, since 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

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.
Voiceless approximants are rarely distinguished from voiceless fricatives. Iaai has an unusually large number of them, with contrasting with . Attested voiceless approximants are:
Examples are:
In Portuguese, the nasal glides and historically became and in some words. In Edo, the nasalized allophones of the approximants and are nasal occlusives, and.
What are transcribed as nasal approximants may include non-syllabic elements of nasal vowels or diphthongs.