Bilabial Trill

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⟩, and the equivalent X-SAMPA symbol is B\.

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

There is also a very rare voiceless alveolar bilabially trilled affricate, (occasionally written "tᵖ") reported from Pirahã and from a few words in the Chapacuran languages Wari’ and Oro Win. The sound also appears as an allophone of the labialized voiceless alveolar stop /tʷ/ of Abkhaz and Ubykh, but in those languages it is more often realised by a doubly articulated stop . In the Chapacuran languages, is reported almost exclusively before rounded vowels such as and .