Bilabial trill

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IPA – number	121
IPA – text	ʙ
IPA – image
Entity	ʙ
X-SAMPA	B\
Kirshenbaum	b<trl>
Sound sample (help·info)

The bilabial trill is a type of consonantal sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ʙ (a character used as a lower case form of B in Jaŋalif and similar alphabets), and the equivalent X-SAMPA symbol is B\.

In many of the languages where the bilabial trill occurs, it occurs only as part of a prenasalised bilabial stop with trilled release, [mbʙ]. This developed historically from a prenasalized stop before a relatively high back vowel, such as [mbu]. In such instances, these sounds are usually still limited to the environment of a following [u].

There is also a very rare voiceless alveolar bilabially trilled affricate, [t̪͡ʙ̥] (occasionally written "t^p") reported from a few words in the Chapacuran languages, Wari’ and Oro Win. The sound also appears as an allophone of the labialized voiceless alveolar plosive /tʷ/ of Abkhaz and Ubykh, but in those languages it is more often realised by a doubly articulated stop [t͡p]. In the Chapacuran languages, [tʙ̥] is reported almost exclusively before rounded vowels such as [o] and [y].

Features

Features of the bilabial trill:

• Its manner of articulation is trill, which means it is produced by vibrations of the articulators. 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 type is voiced, which means the vocal cords are vibrating during the articulation.
• It is an oral consonant, which means air is allowed to escape through the mouth.
• It is a central consonant, which means it is produced by allowing the airstream to flow over the middle of the tongue, rather than the sides.
• The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.

Occurrence

See also

• List of phonetics topics

References

Bibliography

• Ladefoged, Peter (2005). Vowels and Consonants (Second ed.). Blackwell. 

External links

• Oro Win recordings