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 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, 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, 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 or as a closed syllable ending in a consonant .Template:Sfnp

It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel, but Romanian contrasts the diphthong with , 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 in singular-plural pairs), there are phonetic differences between the pair:Template:Sfnp

• has a greater duration than
• The transition between the two elements is longer and faster for than with the former having a higher F2 onset (greater constriction of the articulators).

Although a phonological parallel exists between and , the production and perception of phonetic contrasts between the two is much weaker, likely because of lower lexical load for , 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 ( Template:Gloss vs. 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 and : (Template:Gloss) vs. Template:Gloss,Template:Sfnp and although there is dialectal and idiolectal variation, speakers may also exhibit other near-minimal pairs like Template:Gloss vs. Template:Gloss.Template:Sfnp One potential minimal pair (depending on dialect) is Template:Gloss vs. 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 (), like in Rioplatense Spanish.

See also

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

Sources

• Template:Open access
• Template:SOWL