Semivowel

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. Examples of semivowels in English are the consonants y and w, in yes and west, respectively. Written /j w/ in IPA, y and w are near to the vowels ee and oo in seen and moon, written /iː uː/ in IPA. The term glide may alternatively refer to any type of transitional sound, not necessarily a semivowel. 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. Examples of semivowels in English are the consonants y and w, in yes and west, respectively. Written /j w/ in IPA, y and w are near to the vowels ee and oo in seen and moon, written /iː uː/ in IPA. The term glide may alternatively refer to any type of transitional sound, not necessarily a semivowel. Semivowels form a subclass of approximants. Although 'semivowel' and 'approximant' are sometimes treated as synonymous, 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, Ladefoged & Maddieson (1996) do not consider the labiodental approximant to be a semivowel while Martínez Celdrán (2004) proposes that it should be considered one. In the International Phonetic Alphabet, the diacritic attached to non-syllabic vowel letters is an inverted breve placed below the symbol representing the vowel: .mw-parser-output .monospaced{font-family:monospace,monospace}U+032F  ̯  .mw-parser-output .smallcaps{font-variant:small-caps}COMBINING INVERTED BREVE BELOW. When there is no room for the tack under a symbol, it may be written above, using U+0311  ̑  COMBINING INVERTED BREVE. Before 1989, non-syllabicity was represented by (U+0306  ̆  COMBINING BREVE), which now stands for extra-shortness. Additionally, there are dedicated symbols for four semivowels that correspond to the four close cardinal vowel sounds: The pharyngeal approximant is also equivalent to the semivowel articulation of the open back unrounded vowel . In addition, some authors consider the rhotic approximants , to be semivowels corresponding to R-colored vowels such as . As mentioned above, the labiodental approximant is considered a semivowel in some treatments. An unrounded central semivowel, , equivalent to , is uncommon, though rounded (or ), equivalent to , is found in Swedish and Norwegian. Semivowels, by definition, contrast with vowels by being non-syllabic. In addition, they are usually shorter than vowels. In languages as diverse as Amharic, Yoruba, and Zuni, semivowels are produced with a narrower constriction in the vocal tract than their corresponding vowels. 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 . It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel, but Romanian contrasts the diphthong /e̯a/ with /ja/, 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 /e/ in singular-plural pairs), there are phonetic differences between the pair: