Semivowel

Template:Manner of articulation

In phonetics and phonology, a semivowel (or glide) is a sound, such as English /w/ or /j/, that is phonetically similar to a vowel sound but functions as the syllable boundary rather than as the nucleus of a syllable.^[1]

Classification

Semivowels form a subclass of approximants.^[2]^[3] Although "semivowel" and "approximant" are sometimes treated as synonymous,^[4] most authors agree that not all approximants are semivowels, although the exact details may vary from author to author. For example, Ladefoged & Maddieson (1996) don't consider the labiodental approximant [ʋ] to be a semivowel,^[5] while Martínez-Celdrán:2004) proposes that it should be considered one.^[6]

In the International Phonetic Alphabet, the diacritic attached to non-syllabic vowel letters is Template:IPA diacritic description. Additionally, there are dedicated letters for four semivowels that correspond to the four close cardinal vowel sounds:^[3]

Semivowel (non-syllabic)	Vowel (syllabic)
[j] (palatal approximant)	[i] (close front unrounded vowel)
[ɥ] (labio-palatal approximant)	[y] (close front rounded vowel)
[ɰ] (velar approximant)	[ɯ] (close back unrounded vowel)
[w] (labiovelar approximant)	[u] (close back rounded vowel)

In addition, some authors^[5]^[6] consider the rhotic approximants [ɹ], [ɻ ] to be semivowels corresponding to R-colored vowels such as [ɚ]. As mentioned above, the labiodental approximant [ʋ] is considered a semivowel in some treatments. A central semivowel, [ ȷ̈] (also written [ ɉ]), is uncommon. The semivowel corresponding to the close mid front unrounded vowel,^{[clarification needed]} here provisionally defined as "semipalatal semilateral" approximant, is currently attested only^{[dubious – discuss]} in some varieties of Venetian as an allophone of the lateral consonant /l/ and can also be reduced to zero.^{[citation needed]}

Contrast with vowels

Semivowels, by definition, contrast with vowels by being non-syllabic. In addition, they are usually shorter than vowels.^[2] In languages as diverse as Amharic, Yoruba, and Zuni, semivowels are produced with a narrower constriction in the vocal tract than their corresponding vowels.^[5] 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 /flaɪ̯/, or as a closed syllable ending in a consonant /flaj/.^[7]

It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel,^{[citation needed]} however, Romanian contrasts the diphthong /e̯a/ with /ja/, a perceptually similar approximant–vowel sequence. The diphthong is analyzed as a single segment while the approximant–vowel sequence is analysed as two separate segments. In addition to phonological justifications for the distinction (such as the diphthong alternating with /e/ in singular–plural pairs), there are phonetic differences between the pair:^[8]

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

Although a phonological parallel exists between /o̯a/ and /wa/, the production and perception of phonetic contrasts between the two is much weaker, likely due to a lower lexical load for /wa/ (which is limited largely to loanwords from French) and a difficulty in maintaining contrasts between two back rounded glides in comparison to front ones.^[9]

Contrast with fricatives/spirant approximants

According to the standard definitions, semivowels (such as [j]) contrast with fricatives (such as [ʝ]) in that fricatives produce turbulence, while 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.^[10] Though the spirant approximant is more constricted (having a lower F2 amplitude), longer, and unspecified for rounding (e.g. viuda [ˈbjuða] 'widow' vs ayuda [aˈʝʷuða] 'help'),^[11] 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 /l/ and /n/: enyesar [ẽɲɟʝeˈsaɾ] ('to plaster') aniego [ãnjeɣo] ('flood')^[12] and, although there is dialectal and ideolectal variation, speakers may also exhibit other near-minimal pairs like abyecto ('abject') vs abierto ('opened').^[13] One potential minimal pair (depending on dialect) is ya visto [(ɟ)ʝaˈβisto] ('I have already seen') vs y ha visto [jaˈβisto] ('and he has seen').^[14] Again, this 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 (e.g. [ʒ]).

Bibliography

Bowen, J. Donald; Stockwell, Robert P. (1955), "The Phonemic Interpretation of Semivowels in Spanish", Language, 31 (2), Linguistic Society of America: 236–240, doi:10.2307/411039, JSTOR 411039
Chitoran, Ioana (2002), "A perception-production study of Romanian diphthongs and glide-vowel sequences", Journal of the International Phonetic Association, 32 (2): 203–222, doi:10.1017/S0025100302001044
Crystal, David (2003), A dictionary of linguistics & phonetics (fifth ed.), Wiley-Blackwell, ISBN 0-631-22664-8
Cohen, Antonie (1971), The phonemes of English: a phonemic study of the vowels and consonants of standard English (third ed.), Springer, ISBN 90-247-0639-4
Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19815-6.
Martínez-Celdrán, Eugenio (2004), "Problems in the Classification of Approximants", Journal of the International Phonetic Association, 34 (2): 201–210, doi:10.1017/S0025100304001732
Meyer, Paul Georg (2005), Synchronic English Linguistics: An Introduction (third ed.), Tübingen: Gunter Narr Verlag, ISBN 3-8233-6191-0
Saporta, Sol (1956), "A Note on Spanish Semivowels", Language, 32 (2), Linguistic Society of America: 287–290, doi:10.2307/411006, JSTOR 411006
Trager, George (1942), "The Phonemic Treatment of Semivowels", Language, 18 (3), Linguistic Society of America: 220–223, doi:10.2307/409556, JSTOR 409556