Semivowel

In phonetics and phonology, a semivowel, glide or semiconsonant is a sound that is phonetically similar to a vowel sound but functions as the syllable boundary, rather than as the nucleus of a syllable.Template:Sfnp Examples of semivowels in English are y and w in yes and west, respectively. Written Template:IPAc-en in IPA, y and w are near to the vowels ee and oo in seen and moon, written Template:IPAc-en in IPA. The term glide may alternatively refer to any type of transitional sound, not necessarily a semivowel.Template:Sfnp

Classification

Semivowels form a subclass of approximants.Template:SfnpTemplate:Sfnp Although "semivowel" and "approximant" are sometimes treated as synonymous,Template:Sfnp most authors use the term "semivowel" for a more restricted set; there is no universally agreed-upon definition, and the exact details may vary from author to author. For example, Template:Harvcoltxt do not consider the labiodental approximant {{#invoke:IPA|main}} to be a semivowel.Template:Sfnp

In the International Phonetic Alphabet, the diacritic attached to non-syllabic vowel letters is an inverted breve placed below the symbol representing the vowel: Template:Unichar. When there is no room for the inverted breve under a symbol, it may be written above, using Template:Unichar. Before 1989, non-syllabicity was represented by Template:Unichar, which now stands for extra-shortness.

Additionally, there are dedicated symbols for four semivowels that correspond to the four close cardinal vowel sounds:Template:Sfnp

Semivowel (non-syllabic)	Vowel (syllabic)
Template:IPAblink (palatal approximant)	Template:IPAblink (close front unrounded vowel)
Template:IPAblink (labio-palatal approximant)	Template:IPAblink (close front rounded vowel)
Template:IPAblink (velar approximant)	Template:IPAblink (close back unrounded vowel)
Template:IPAblink (labiovelar approximant)	Template:IPAblink (close back rounded vowel)

Some authors argue for the recognition of additional semivowels:

• The rhotic approximants Template:IPAalink and Template:IPAalink, considered to be semivowels corresponding to r-colored vowels such as Template:Angbr IPA or Template:Angbr IPA.Template:SfnpTemplate:Sfnp
• The pharyngeal approximant Template:IPAalink, considered to be the semivowel corresponding to the open back vowel Template:IPAalink,Template:Sfnp which is noted to have distinct pharyngeal features in its articulation.Template:Sfnp
• The post-palatal approximants,<ref name="post-palatal">Instead of "post-palatal", it can be called "retracted palatal", "backed palatal", "palato-velar", "pre-velar", "advanced velar", "fronted velar" or "front-velar". For simplicity, this article uses only the term "post-palatal".</ref> or central semivowels, which may be written as Template:Angbr (diacritics for advancing and retracting), Template:Angbr IPA (diacritics for centralization), or the para-IPA symbols Template:Angbr IPA,<ref>L2/24-049: Unicode support for historical and para-IPA letters</ref> considered to be corresponding to the unrounded Template:IPAalink, compressed Template:IPAalink, and protruded Template:IPAalink close central vowels, respectively.

Contrast with vowels

Semivowels, by definition, contrast with vowels by being non-syllabic. In addition, they are usually shorter than vowels.Template:Sfnp In languages such as Amharic, Yoruba, and Zuni, semivowels are produced with a narrower constriction in the vocal tract than their corresponding vowels.Template:Sfnp Nevertheless, semivowels may be phonemically equivalent with vowels. For example, the English word fly can be considered either as an open syllable ending in a diphthong {{#invoke:IPA|main}} or as a closed syllable ending in a consonant {{#invoke:IPA|main}}.Template:Sfnp

It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel,Template:Citation needed but Romanian contrasts the diphthong {{#invoke:IPA|main}} with {{#invoke:IPA|main}}, a perceptually similar approximant-vowel sequence. The diphthong is analyzed as a single segment, and the approximant-vowel sequence is analyzed as two separate segments.

In addition to phonological justifications for the distinction (such as the diphthong alternating with {{#invoke:IPA|main}} in singular-plural pairs), there are phonetic differences between the pair:Template:Sfnp

• {{#invoke:IPA|main}} has a greater duration than {{#invoke:IPA|main}}
• The transition between the two elements is longer and faster for {{#invoke:IPA|main}} than {{#invoke:IPA|main}} with the former having a higher F2 onset (greater constriction of the articulators).

Although a phonological parallel exists between {{#invoke:IPA|main}} and {{#invoke:IPA|main}}, the production and perception of phonetic contrasts between the two is much weaker, likely because of lower lexical load for {{#invoke:IPA|main}}, which is limited largely to loanwords from French, and speakers' difficulty in maintaining contrasts between two back rounded semivowels in comparison to front ones.Template:Sfnp

Contrast with fricatives/spirant approximants

According to the standard definitions, semivowels (such as Template:IPAblink) contrast with fricatives (such as Template:IPAblink) in that fricatives produce turbulence, but semivowels do not. In discussing Spanish, Martínez Celdrán suggests setting up a third category of "spirant approximant", contrasting both with semivowel approximants and with fricatives.Template:Sfnp Though the spirant approximant is more constricted (having a lower F2 amplitude), longer, and unspecified for rounding ({{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss vs. {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss),Template:Sfnp the distributional overlap is limited. The spirant approximant can only appear in the syllable onset (including word-initially, where the semivowel never appears). The two overlap in distribution after {{#invoke:IPA|main}} and {{#invoke:IPA|main}}: {{#invoke:Lang|lang}} {{#invoke:IPA|main}} (Template:Gloss) vs. {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss,Template:Sfnp and although there is dialectal and idiolectal variation, speakers may also exhibit other near-minimal pairs like {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss vs. {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss.Template:Sfnp One potential minimal pair (depending on dialect) is {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss vs. {{#invoke:Lang|lang}} {{#invoke:IPA|main}} Template:Gloss.Template:Sfnp

Again, it is not present in all dialects. Other dialects differ in either merging the two or enhancing the contrast by moving the former to another place of articulation ({{#invoke:IPA|main}}), like in Rioplatense Spanish.

See also

• Diphthong
• Hiatus (linguistics)
• List of phonetics topics
• Mater lectionis
• Syllabic consonant
• Voiced labio-velar approximant

Sources

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Further reading

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