Voiced bilabial fricative

The voiced bilabial fricative is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨β⟩, and the equivalent X-SAMPA symbol is ⟨B⟩. The symbol ⟨β⟩ is the Greek letter beta. This symbol is also sometimes used to represent the bilabial approximant, though that is more clearly written with the lowering diacritic, ⟨β̞⟩. The bilabial fricative is diachronically unstable and is likely to shift to [v].^[1] In the English language, this sound is not used, but can be made by approximating the normal "v" sound between the two lips.

Features

Features of the voiced bilabial fricative:

• Its manner of articulation is fricative, which means it is produced by constricting air flow through a narrow channel at the place of articulation, causing turbulence.
• Its place of articulation is bilabial, which means it is articulated with both lips.
• Its phonation is voiced, which means the vocal cords vibrate during the articulation.
• It is an oral consonant, which means air is allowed to escape through the mouth only.
• Because the sound is not produced with airflow over the tongue, the central–lateral dichotomy does not apply.
• The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.

Occurrence

In the following transcriptions, the undertack diacritic may be used to indicate an approximant [β̞].

References

Bibliography

• Cruz-Ferreira, Madalena (1995), "European Portuguese", Journal of the International Phonetic Association 25 (2): 90–94, doi:10.1017/S0025100300005223 
• Gussenhoven, Carlos; Aarts, Flor (1999), "The dialect of Maastricht", Journal of the International Phonetic Association 29: 155–166, doi:10.1017/S0025100300006526 
• Hualde, José Ignacio (1991), Basque phonology, New York: Routledge, http://books.google.com/books?id=PBqPPLE2iXEC&l 
• Ladefoged, Peter (2005), Vowels and Consonants (Second ed.), Blackwell 
• Martínez-Celdrán, Eugenio; Fernández-Planas, Ana Ma.; Carrera-Sabaté, Josefina (2003), "Castilian Spanish", Journal of the International Phonetic Association 33 (2): 255–259, doi:10.1017/S0025100303001373 
• Picard, Marc (1987), "On the Palatalization and Fricativization of w", International Journal of American Linguistics 53 (3): 362–365, doi:10.1086/466063 
• Pope, Mildred (1966), From Latin to Modern French, Manchester: Manchester University Press 
• Merrill, Elizabeth (2008), "Tilquiapan Zapotec", Journal of the International Phonetic Association 38 (1): 107–114, doi:10.1017/S0025100308003344 
• Wheeler, Max W (2005), The Phonology Of Catalan, Oxford: Oxford University Press, ISBN 0199258147 

See also

• List of phonetics topics