Voiceless bilabial trill
The voiceless 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 . This sound is typologically extremely rare. It occurs in languages such as Pará Arára and Sercquiais. Only a few languages contrast voiced and voiceless bilabial trills phonemically – e.g. Mangbetu of Congo and Ninde of Vanuatu. There is also a very rare voiceless alveolar bilabially trilled affricate, (written in Everett & Kern) reported from Pirahã and from a few words in the Chapacuran languages Wariʼ and Oro Win. The sound also appears  as an allophone of the labialized voiceless alveolar stop 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 . Features. Features of the bilabial trill: