||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (April 2009)|
|From open to closed:|
|Voicelessness (full airstream)|
|Breathy voice (murmur)|
|Modal voice (maximum vibration)|
|Creaky voice (restricted airstream)|
|Glottalized (blocked airstream)|
|Faucalized voice ("hollow")|
|Harsh voice ("pressed")|
|Strident (harsh trilled)|
Breathy voice (also called murmured voice, soughing, or susurration) is a phonation in which the vocal cords vibrate, as they do in normal (modal) voicing, but are held further apart, so that a larger volume of air escapes between them. This produces an audible noise. A breathy-voiced phonation [ɦ] (not actually a fricative, as a literal reading of the IPA chart would suggest) can sometimes be heard as an allophone of English /h/ between vowels, e.g. in the word behind, for some speakers. A stop with breathy-voiced release (symbolized either as [bʱ], [dʱ], [ɡʱ], [mʱ] etc. or as [b̤], [d̤], [ɡ̈], [m̤] etc.) is like aspiration in that it delays the onset of full voicing. Breathy-voiced vowels are written [a̤], [e̤], etc.
In the context of the Indo-Aryan languages (e.g. Sanskrit and Hindi) and comparative Indo-European studies, breathy-voiced consonants are often called voiced aspirated, as in e.g. the Hindi and Sanskrit stops normally denoted bh, dh, ḍh, jh, and gh and the reconstructed Proto-Indo-European phoneme gʷh. From an articulatory perspective this terminology is incorrect, as breathy voice is a different type of phonation from aspiration. However, breathy-voiced and aspirated stops are acoustically similar in that in both cases there is an audible period of breathiness following the stop, and in the history of various languages (e.g. Ancient Greek, Mandarin Chinese), breathy-voiced stops have subsequently developed into voiceless aspirated stops.
Methods of production 
There are several ways to produce breathy-voiced sounds like [ɦ]. One is to hold the vocal cords apart, so that they are lax as they are for [h], but to increase the volume of airflow so that they vibrate loosely. A second is to bring the vocal cords closer together along their entire length than in voiceless [h], but not as close as in modally voiced sounds such as vowels. This results in an airflow intermediate between [h] and vowels, and is the case with English intervocalic /h/. A third is to constrict the glottis, but separate the arytenoid cartilages that control one end. This results in the vocal cords being drawn together for voicing in the back, but separated to allow the passage of large volumes of air in the front. This is the situation with Hindi.
The distinction between the latter two of these realizations, vocal cords somewhat separated along their length (breathy voice) and vocal cords together with the arytenoids making an opening (whispery voice), is phonetically relevant in White Hmong.
Breathy voice as a phonological property 
A number of languages use breathy voicing in a phonologically contrastive way. Many Indo-Aryan languages, such as Hindi, typically have a four-way contrast among plosives and affricates (voiced, breathy voiced, tenuis, aspirated) and a two-way contrast among nasals (voiced, breathy voiced). The Nguni languages in the southern Bantu languages family, including Phuthi, Xhosa, Zulu, Ndebele and Swati, also have contrastive breathy voice. In the case of Xhosa, there is a four-way contrast analogous to Indic in oral clicks, and similarly a two-way contrast among nasal clicks, but a three-way contrast among plosives and affricates (breathy voiced, aspirated, and ejective), and two-way contrasts among fricatives (voiceless and breathy voiced) and nasals (voiced and breathy voiced).
In some Bantu languages, historically breathy-voiced stops have been phonetically devoiced, but the four-way contrast in the system has been retained. In all five of the southeastern Bantu languages named, the breathy voiced stops (even if they are realised phonetically as devoiced aspirates) have a marked tone-lowering (or tone-depressing) effect on the following tautosyllabic vowels. For this reason, such stop consonants are frequently referred to in the local linguistic literature as 'depressor' stops.
Swati, and even more so Phuthi, display good evidence that breathy voicing can be used as a morphological property independent of any consonant voicing value. For example, in both languages, the standard morphological mechanism for achieving the morphosyntactic copula is to simply execute the noun prefix syllable as breathy voiced (or 'depressed').
See also 
- Fulop & Golston (2008), Breathy and whispery voicing in White Hmong, http://zimmer.csufresno.edu/~chrisg/index_files/FulopGolston2009.pdf. Retrieved 17 June 2012.
- Traill, Anthony, James S. M. Khumalo and Paul Fridjhon (1987). Depressing facts about Zulu. African Studies 46: 255-274.
- Callou, Dinah. Leite, Yonne. "Iniciação à Fonética e à Fonologia". Jorge Zahar Editor 2001, p. 20
- Ladefoged, Peter; Maddieson, Ian (1996). The Sounds of the World's Languages. Oxford: Blackwell. ISBN 0-631-19814-8.