# Voiced bilabial trill

The voiced bilabial trill is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents the sound is ⟨ʙ⟩, a small capital version of the Latin letter b, and the equivalent X-SAMPA symbol is B\.

## Features

Features of the voiced bilabial trill:
* Its manner of articulation is trill, which means it is produced by directing air over an articulator so that it vibrates. In most instances, it is only found as the trilled release of a prenasalized stop.
* 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.
* Its airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the intercostal muscles and abdominal muscles, as in most sounds.

## Varieties

| IPA | Description |
| ʙ | Voiced bilabial trill |
| ᵐʙ | Prenasalized voiced bilabial trill |

## Occurrences

Occurrences of [ʙ] in various languages :
| Affiliation | Language | Language | Word | IPA | Meaning | Notes |
| Bantoid | Medumba | Medumba | mʙʉ | [mʙʉ́] | 'dog' | |
| Bantoid | Ngwe | Lebang dialect | [àʙɨ́ ́] | [àʙɨ́ ́] | 'ash' | |
| Mura | Pirahã | Pirahã | kaoáíbogi | [kàò̯áí̯ʙòˈɡì] | 'evil spirit' | Allophone of /b/ before /o/ |
| Mura | Pirahã | Pirahã | ʔíbogi | | 'milk' | Allophone of /b/ before /o/ |
| Uralic | Komi-Permyak | Komi-Permyak | Бунгаг | [ʙuŋɡaɡ] | 'dung beetle' | Generally paralinguistic. This is the only true word it is found in. |
| Senu River | Kwomtari | Kwomtari | | | | |
| Skou | Sko | Sko | | | | |
The Knorkator song "[Buchstabe]" (the actual title is a glyph) on the 1999 album Hasenchartbreaker uses a similar sound (though linguolabial instead of bilabial) to replace "br" in a number of German words (e.g. [ˈʙaːtkaɐ̯tɔfəln] for Bratkartoffeln).

### Prenasalized

Occurrences of [ᵐʙ] in various languages :
| Affiliation | Language | Language | Word | IPA | Meaning | Notes |
| Oceanic | Kele | Kele | [ᵐʙulim] | [ᵐʙulim] | 'face' | And other languages of the Admiralty Islands |
| Oceanic | Titan | Titan | [ᵐʙutukei] | [ᵐʙutukei] | 'wooden plate' | |
| Oceanic | Unua | Unua | [ᵐʙue] | [ᵐʙue] | 'pig' | |
| Oceanic | Ahamb | Ahamb | [nãᵐʙwas] | [nãᵐʙwas] | 'pig' | Phonemic; contrasts between /ᵐʙ/ and /ʙ̥/. |
| Border | Kilmeri | Kilmeri | | | | |

### Prestopped trills and stops with trill release

Occurrences of bilabial trills with a stop in various languages :
| Affiliation | Language | Word | IPA | Meaning | Notes |
| Naga | Sangtam | [t͡ʙàŋ] | [t͡ʙàŋ] | 'needle' | Phonemic as /t͡ʙ/, contrasts with /t͡ʙ̥ʰ/. |
| Qiangic | Lizu | TU, | [tʙ̩˥˩] | 'bean' | Syllabic; allophone of /u/ after initial /pʰ, p, b, tʰ, t, d/. |
| Qiangic | Namuyi | tbĭh | [t͡ʙ̩˨] | 'to slaughter' | Phonemic according to Pavlík (2017) occurring before /u/ or as a syllabic consonant. [ʙ] is classified as an allophone of /u/ following a /p/, /b/, /t/ or /d/ in the phonemic analysis of Huáng (1992:673–674), and Yǐn (2016). No bilabial trills are present in the phonemic analysis of Nishida (2013). |
| Qiangic | Namuyi | dbù | [d͡ʙu˥˨] | 'wild' | Phonemic according to Pavlík (2017) occurring before /u/ or as a syllabic consonant. [ʙ] is classified as an allophone of /u/ following a /p/, /b/, /t/ or /d/ in the phonemic analysis of Huáng (1992:673–674), and Yǐn (2016). No bilabial trills are present in the phonemic analysis of Nishida (2013). |
| Qiangic | Namuyi | pbĭh | [p͡ʙ̩] | 'to deliver' | Phonemic according to Pavlík (2017) occurring before /u/ or as a syllabic consonant. [ʙ] is classified as an allophone of /u/ following a /p/, /b/, /t/ or /d/ in the phonemic analysis of Huáng (1992:673–674), and Yǐn (2016). No bilabial trills are present in the phonemic analysis of Nishida (2013). |
| Qiangic | Namuyi | [b͡ʙuda] | [b͡ʙuda] | surname | Phonemic according to Pavlík (2017) occurring before /u/ or as a syllabic consonant. [ʙ] is classified as an allophone of /u/ following a /p/, /b/, /t/ or /d/ in the phonemic analysis of Huáng (1992:673–674), and Yǐn (2016). No bilabial trills are present in the phonemic analysis of Nishida (2013). |
| Qiangic | Pumi | biiv | [pʙ̩˥] | 'to dig' | Syllabic; allophone of /ə/ after /pʰ, p, b, tʰ, t, d/. |

## Phonology

In many of the languages in which the bilabial trill occurs, it occurs only as part of a prenasalized bilabial stop with trilled release, [mbʙ]. That developed historically from a prenasalized stop before a relatively high back vowel like [mbu]. In such instances, the sounds are usually still limited to the environment of a following [u]. However, the trills in Mangbetu may precede any vowel and are sometimes preceded by only a nasal.