Semivowel

Semivowels form a subclass of approximants. Although "semivowel" and "approximant" are sometimes treated as synonymous, 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, do not consider the labiodental approximant to be a semivowel. In the International Phonetic Alphabet, the diacritic attached to non-syllabic vowel letters is an inverted breve placed below the symbol representing the vowel: . When there is no room for the inverted breve under a symbol, it may be written above, using . Before 1989, non-syllabicity was represented by , which now stands for extra-shortness. Additionally, there are dedicated symbols for four semivowels that correspond to the four close cardinal vowel sounds: Some authors argue for the recognition of additional semivowels: • The rhotic approximants and , considered to be semivowels corresponding to r-colored vowels such as or . • The pharyngeal approximant , considered to be the semivowel corresponding to the open back vowel , which is noted to have distinct pharyngeal features in its articulation. • The post-palatal approximants, or central semivowels, which may be written as (diacritics for advancing and retracting), (diacritics for centralization), or the para-IPA symbols , considered to be corresponding to the unrounded , compressed , and protruded 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. In languages such 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 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: • 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. ==Contrast with fricatives and spirant approximants==

According to the standard definitions, semivowels (such as ) contrast with fricatives (such as ) in that fricatives produce turbulence, but semivowels do not. In discussing Spanish, suggested setting up a third category of spirant approximants (such as ) contrasting with both semivowel approximants and fricatives, described as "non-rhotic central approximants". revived the term "frictionless continuant" – which historically referred more broadly to non-lateral approximants – to distinguish this class, and continued to use the term in subsequent works. Though spirant approximants are more constricted (having a lower F2 amplitude), longer, and unspecified for rounding ( vs. ), the distributional overlap is limited. Spirant approximants can only appear in syllable onset (including word-initially, where semivowels never appear). The two overlap in distribution after and : () vs. , and although there is dialectal and idiolectal variation, speakers may also exhibit other near-minimal pairs like vs. . One potential minimal pair (depending on dialect) is vs. . Again, it is not present in all dialects. Other dialects differ in either merging the two, or conversely by enhancing the contrast through moving the fricative to another place of articulation (such as , a feature called ), like in Rioplatense Spanish (some dialects of Rioplatense, such as the Buenos Aires dialect, even devoice to , a feature called ). ==See also==