A 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 either a Latin or Greek-style beta, .
This letter is also often used to represent a voiced bilabial approximant, though that is more precisely written with a lowering diacritic, that is . This sound may also be transcribed as an advanced labiodental approximant , in which case the diacritic is again frequently omitted, since no contrast is likely. It has been proposed that either a turned or reversed , among others, be used as a dedicated symbol for the bilabial approximant; however, despite occasional usage, none have gained general acceptance.
It is extremely rare for a language to make a phonemic contrast between a voiced bilabial fricative and a bilabial approximant. The Mapos Buang language of New Guinea contains this contrast. Its bilabial approximant is analyzed as filling a phonological gap in the labiovelar series of the consonant system rather than the bilabial series. Proto-Germanic and Proto-Italic are reconstructed as having had a contrast between the voiced bilabial fricative and the voiced labial–velar approximant , albeit with being an allophone for another consonant in both cases. In Bashkir language, it is an intervocal allophone of , and it is contrastive with : , .
A bilabial fricative is diachronically unstable (likely to be considerably varied between dialects of a language that makes use of it) and is likely to shift to .
The sound is not the primary realization of any sound in English dialects except for Chicano English, but it can be produced by approximating the normal English between the lips; it can also sometimes occur as an allophone of after bilabial consonants.
Features
Features of a voiced bilabial fricative:
Occurrence
Voiced bilabial fricative
{| class="wikitable mw-collapsible"
!colspan=2| Language !! Word !! IPA !! Meaning !! Notes
|-
|colspan=2| Akei ||colspan=2| || 'four' ||
|-
|colspan=2| Alekano || || || 'nothing' ||
|-
|colspan=2| Angor || || || 'horn' ||
|-
| Bengali || Eastern dialects || || || 'Visa' || Allophone of in Bangladesh and Tripura; used in Western dialects.
|-
|colspan=2| Berta ||colspan=2| || 'no' ||
|-
|colspan=2| Catalan || || || 'before' || Approximant or fricative. Allophone of . Mainly found in betacist ( and merging) dialects. See Catalan phonology
|-
|rowspan=2| Chinese dialects || Fuzhou || / || || 'eighth day of the month' || Allophone of and in certain intervocalic positions.
|-
|colspan=2| Comorian || || || 'to love' || Contrasts with both and
|-
|rowspan=2| Coptic || Bohairic || || ||rowspan=2| 'brick' || Shifted to with a syllable coda allophone of in a later stage.
|-
| Sahidic || || ||
|-
|colspan=2| Dahalo ||colspan=2 align=center| || 'to want' || Weak fricative or approximant. It is a common intervocalic allophone of , and may be simply a plosive instead. || || || 'Ewe' || Contrasts with both and
|-
|colspan=2| Fijian || || || 'shoe' ||
|-
|colspan=2| German || || || 'but' || Intervocalic and pre-lateral allophone of in casual speech. || / || || 'Kobe' || Allophone of only in fast speech between vowels. See Japanese phonology
|-
|colspan=2| Kabyle || || || 'to cut' ||
|-
|colspan=2| Kinyarwanda || || || 'children' ||
|-
|colspan=2| Korean || / / || || 'later' || Intervocalic allophone of before and . See Korean phonology
|-
|Luhya || Wanga Dialect || || || 'title for a king' ||
|-
| colspan="2" |Mapos Buang || || || 'Saturday'|| Allophone of . See Portuguese phonology
|-
| Ripuarian || Colognian || || || 'wine' || Allophone of syllable-initial for some speakers; can be instead. See Colognian phonology
|-
| Sardinian || Logudorese || || || 'pope' || Intervocalic allophone of as well as word-initial when the preceding word ends with a vowel and there is no pause between the words. || || || 'body' || Allophone of before and after rounded vowels.
|
|
|'work party held by one who wants to have the land ploughed or cultivated'
|Contrasts with and
|-
| Zapotec || Tilquiapan || || || || Allophone of
|}
Bilabial approximant
{| class="wikitable"
!colspan=2| Language !! Word !! IPA !! Meaning !! Notes
|-
| colspan="2" | Amharic || || || 'flower' || Allophone of medially between sonorants. || || || 'daughter' || Allophone of
|-
|colspan=2| Catalan || Western || || || 'wood' || Corresponds to and in other dialects.
|-
|colspan=2| Kyrgyz
|
|
|'yes'
|Allophone of medially between vowels.
|-
|colspan=2| Limburgish || || || 'to want' || The example word is from the Maastrichtian dialect.
|-
|colspan=2| Lombard || || || 'he was going away' || Regular pronunciation of when intervocalic. Used also as an allophone for other positions.
|-
| colspan="2" |Mapos Buang || || || 'smoke' || Weakly rounded; contrasts with . || || || 'lava' || Ranges from close fricative to approximant. Allophone of . See Spanish phonology
|-
| Swedish || Central Standard || || || 'Saudi Arabia' || Allophone of in casual speech. See Swedish phonology
|-
|colspan=2| Ukrainian || || || 'she' || An approximant; the most common prevocalic realization of . Can vary with labiodental .