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\.

Contents

• Features
• Occurrence
• References

In many of the languages where the bilabial trill occurs, it only occurs as part of a prenasalized 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]. However, the trills in Mangbetu may precede any vowel and are only sometimes preceded by a nasal.

A few languages, such as Mangbetu of Congo and Ninde of Vanuatu, have both a voiced and a voiceless bilabial trill.

There is also a very rare voiceless alveolar bilabially trilled affricate, [t̪͡ʙ̥] (written ⟨tᵖ̃⟩ in Everett & Kern) 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 [t͡p]. In the Chapacuran languages, [tʙ̥] is reported almost exclusively before rounded vowels such as [o] and [y].