Semivowel - Contrast With Vowels

Contrast With Vowels

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 /flaɪ̯/, or as a closed syllable ending in a consonant /flaj/.

It is unusual for a language to contrast a semivowel and a diphthong containing an equivalent vowel, 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:

• /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.