Voice onset time
From Freepedia
In phonetics, voice onset time, commonly abbreviated VOT, is the length of time that passes between when a consonant is released and when voicing, the vibration of the vocal cords, begins.
The three major phonation types of stops can be analyzed in terms of their voice onset time.
- Simple voiceless plosives, sometimes called tenuis, have a voice onset time at or near zero, meaning that the voicing of a following sonorant (such as a vowel) begins at or near to when the stop is released. (Usually an offset of less than 15-30 ms is inaudible, and for all practical purposes counts as zero.)
- Aspirated plosives have a voice onset time greater than this amount, called a positive VOT. The period between the release of the stop and the onset of voicing is what constitutes the aspiration. The longer the VOT, the stronger the aspiration. In Navajo, for example, which is strongly aspirated, aspiration lasts about twice as long as it does in English. Some other languages have weaker aspiration than English.
- Voiced plosives have a voice onset time noticeably less than zero, a negative VOT, meaning the vocal cords start vibrating before the stop is released. With a fully voiced stop, the VOT coincides with the onset of the stop; with a partially voiced stop, such as English [b, d, g] in initial position, voicing begins sometime during the closure (occlusion) of the consonant.
- "Full voicing" is not the limit. A voicing duration greater than the length of the plosive may manifests itself as prenasalization. (On the other hand, stronger voicing of an already fully voiced plosive may result in implosion.) Throughout much of Melanesia, the voicing contrast is prenasalized vs unvoiced, and in many languages prenasalized and modally voiced consonants are allophones.
| Voice Onset Time | Examples | ||||
|---|---|---|---|---|---|
| Strong aspiration | Navajo | ||||
| Mild aspiration | English | Thai | |||
| Tenuis | Navajo | Spanish | Thai | ||
| Partially voiced | English | ||||
| Fully voiced | Spanish | N. Japanese | Thai | ||
| Prenasalized | N. Japanese |
These concepts apply to fricatives and other consonants as well, but usually aspiration and prenasalization is only relevant for plosives and affricates.
