Semivowels (also called semiconsonants or glides, though these are now dispreferred) are non-syllabic vowels that form diphthongs with syllabic vowels. They may be contrasted with approximants, which are similar to but closer than vowels or semivowels and behave as consonants. Semivowels are normally written by adding the IPA non-syllabic mark to a vowel symbol, but often for simplicity the vowel symbol alone is written.

To illustrate, the English word wow may be transcribed as (or abbreviated to ). Even though both the and the are similar to the vowel , the transcription indicates that the initial segment is considered to be a consonant by the transcriber, while the final segment is considered to form a diphthong with the preceding vowel. The approximant is more constricted and therefore more consonant-like than the semivowel . (Using the transcription for the diphthong rather than as one might expect is a minor phonetic point. See diphthong for details.)

Because they are so similar phonetically, the concepts of semivowel and approximant are often used interchangeably. In this conflated usage, semivowels are defined as those approximants that correspond phonetically to specific close vowels. These are corresponding to ^*" target="_blank" >for ^*; and for . (See approximant for details.) However, languages such as Nepali and Samoan have additional semivowels such as and that correspond to mid vowels, and which other than being non-syllabic are not at all like consonants.

Examples

Close semivowels

• English eye
• English cow
• Dutch ui "onion"

Close vs. mid semivowels

• Samoan ’ai "probably"
• Samoan ’ae "but"
• Samoan ’auro "gold"
• Samoan ao "a cloud"

See also

• List of phonetics topics
• Diphthong

Consonants

Halvvokal | Halbvokal | Semi-voyelle | 반모음 | 半母音 | Halvvokal | Semivocală | Puolivokaali | Halvvokal