Voiced bilabial fricative

Voiced bilabial fricative
β
IPA Number	127
Encoding
Entity (decimal)	β
Unicode (hex)	U+03B2
X-SAMPA	B
Braille
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Voiced bilabial approximant
β̞
Audio sample
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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⟩ (or more properly ⟨ꞵ⟩), 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, that is ⟨β̞⟩. Theoretically, it could also be transcribed as an advanced labiodental approximant ⟨ʋ̟⟩, but this symbol is hardly (if ever) used in this manner. Very few languages are known to make a phonemic contrast between the voiced bilabial fricative and the bilabial approximant, but one language that does make this contrast is the Tarahumara language of the Uto-Aztecan family. The bilabial fricative is diachronically unstable and is likely to shift to [v]. 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 is used to indicate an approximant [β̞].

Language		Word	IPA	Meaning	Notes
Akei		[βati]		'four'
Alekano		hanuva	[hɑnɯβɑ]	'nothing'
Amharic		አበባ	[aβ̞əβ̞a]	'flower'	Allophone of /b/ medially between sonorants.
Angor		fufung	[ɸuβuŋ]	'horn'
Basque		alaba	[alaβ̞a]	'daughter'	Allophone of /b/
Berta		[βɑ̀lɑ̀ːziʔ]		'no'
Catalan		rebost	[rəˈβ̞ɔst]	'larder'	Fricative or approximant. Allophone of /b/. See Catalan phonology
Chinese	Fuzhou				Allophone of /p/ and /pʰ/ in certain intervocalic positions.
Dahalo		[koːβo]		'to want'
English	Chicano	very	[βɛɹi]	'very'	May be realized as [b] instead.
Ewe		Eʋe	[ɛβɛ]	'Ewe language'	Contrasts with both [v] and [w]
German		aber	[ˈaːβɐ]	'but'	Intervocalic and pre-lateral allophone of /b/ in casual speech. See German phonology
Hopi		tsivot	[tsi:βot]	'five'
Japanese		神戸市/kōbe-shi	[ko̞ːβ̞e̞ ɕi]	'Kobe'	Allophone of /b/ only in fast speech between vowels. See Japanese phonology
Kabyle		bri	[βri]	'to cut'
Kinyarwanda		abana	[aβana]	'children'
Limburgish		wèlle	[ˈβ̞ɛlə]	'to want'	The example word is from the Maastrichtian dialect.
Occitan	Gascon	la-vetz	[laβ̞ets]	'then'	Allophone of /b/
Portuguese	European	sábado	[ˈsaβɐðu]	'Saturday'	Allophone of /b/. See Portuguese phonology
Ripuarian	Colognian	wing	[βɪŋ]	'wine'	Allophone of syllable-initial /v/ for some speakers; can be [ʋ ~ w ~ ɰ] instead. See Colognian phonology
	Kerkrade dialect	sjwaam	[ʃβ̞aːm]	'smoke'	Weakly rounded; contrasts with /v/.
Sardinian	Logudorese dialect	paba	<phonos file="paba.wav">[ˈpäːβä]</phonos>	'Pope'	Intervocalic allophone of /b/ as well as word-initial /p/ when the preceding word ends with a vowel and there is no pause between the words.
Spanish		lava	[ˈläβ̞ä]	'lava'	Ranges from close fricative to approximant.Allophone of /b/. See Spanish phonology
Swedish	Central Standard	aber	[ˈɑːβ̞eɾ]	'problem'	Allophone of /b/ in casual speech. See Swedish phonology
Turkmen		watan	[βatan]	'country'
Zapotec	Tilquiapan				Allophone of /b/

See also

• Index of phonetics articles