In phonetics and phonology, a semivowel or glide, also known as a non-syllabic voiced, 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.틀:Sfnp Examples of semivowels in English are the consonants y and w, in yes and west, respectively. Written 틀:IPAc-en in IPA, y and w are near to the vowels ee and oo in seen and moon, written 틀:IPAc-en in IPA. The term glide may alternatively refer to any type of transitional sound, not necessarily a semivowel.틀:Sfnp
Semivowels form a subclass of approximants.틀:Sfnp틀:Sfnp Although "semivowel" and "approximant" are sometimes treated as synonymous,틀:Sfnp most authors use the term "approximant" for a more restricted set; there is no universally agreed definition, and the exact details may vary from author to author. For example, 틀:Harvcoltxt do not consider the labiodental approximant 틀:IPA to be a semivowel틀:Sfnp while 틀:Harvcoltxt proposes that it should be considered one.틀: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: 틀:Unichar. When there is no room for the tack under a symbol, it may be written above, using 틀:Unichar. Before 1989, non-syllabicity was represented by (틀:Unichar), which now stands for extra-shortness.
|Semivowel (non-syllabic)||Vowel (syllabic)|
|틀:IPAblink (palatal approximant)||틀:IPAblink (close front unrounded vowel)|
|틀:IPAblink (labio-palatal approximant)||틀:IPAblink (close front rounded vowel)|
|틀:IPAblink (velar approximant)||틀:IPAblink (close back unrounded vowel)|
|틀:IPAblink (labiovelar approximant)||틀:IPAblink (close back rounded vowel)|
In addition, some authors틀:Sfnp틀:Sfnp consider the rhotic approximants 틀:IPAblink, 틀:IPAblink to be semivowels corresponding to R-colored vowels such as 틀:IPAblink. As mentioned above, the labiodental approximant 틀:IPAblink is considered a semivowel in some treatments. An unrounded central semivowel, 틀:IPA, equivalent to 틀:IPA, is uncommon, though rounded 틀:IPA (or 틀:IPA), equivalent to 틀:IPA, is found in Swedish and Norwegian.
Contrast with vowels
Semivowels, by definition, contrast with vowels by being non-syllabic. In addition, they are usually shorter than vowels.틀:Sfnp In languages as diverse as Amharic, Yoruba, and Zuni, semivowels are produced with a narrower constriction in the vocal tract than their corresponding vowels.틀: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 틀:IPA or as a closed syllable ending in a consonant 틀:IPA.틀:Sfnp
It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel,틀:Citation needed but Romanian contrasts the diphthong 틀:IPA with 틀:IPA, 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.
- 틀:IPA has a greater duration than 틀:IPA
- The transition between the two elements is longer and faster for 틀:IPA than 틀:IPA with the former having a higher F2 onset (greater constriction of the articulators).
Although a phonological parallel exists between 틀:IPA and 틀:IPA, the production and perception of phonetic contrasts between the two is much weaker, likely because of lower lexical load for 틀:IPA, which is limited largely to loanwords from French, and a difficulty in maintaining contrasts between two back rounded semivowels in comparison to front ones.틀:Sfnp
Contrast with fricatives/spirant approximants
According to the standard definitions, semivowels (such as 틀:IPA) contrast with fricatives (such as 틀:IPA) 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.틀:Sfnp Though the spirant approximant is more constricted (having a lower F2 amplitude), longer, and unspecified for rounding (viuda 틀:IPA 'widow' vs. ayuda 틀:IPA 'help'),틀: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 틀:IPA and 틀:IPA: enyesar 틀:IPA ('to plaster') aniego 틀:IPA ('flood')틀:Sfnp and although there is dialectal and ideolectal variation, speakers may also exhibit other near-minimal pairs like abyecto ('abject') vs abierto ('opened').틀:Sfnp One potential minimal pair (depending on dialect) is ya visto 틀:IPA ('already seen') vs y ha visto 틀:IPA ('and he has seen').틀:Sfnp Again, it is not present in all dialects. Other dialects differ in either merging the two or in enhancing the contrast by moving the former to another place of articulation (틀:IPA).
- Hiatus (linguistics)
- List of phonetics topics
- Mater lectionis
- Syllabic consonant
- Voiced labio-velar approximant
- 틀:Citation 틀:Open access