Itsphonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
It is anoral consonant, which means that air is not allowed to escape through the nose.
Because the sound is not produced with airflow over the tongue, thecentral–lateral dichotomy does not apply.
There is also a very rare voiceless bilabially post-trilled dental or alveolar stop,[t̪͡ʙ̥] (written ⟨tᵖ̃⟩ in Everett & Kern) reported from a few words in theChapacuran languagesWariʼ,Itene (More),[10] andOro Win, as well asSangtam, aNaga language. The sound also appears as anallophone of the labializedvoiceless alveolar stop/tʷ/ ofAbkhaz andUbykh, but in those languages it is more often realised by adoubly articulated stop[t͡p]. In the Chapacuran languages,[tʙ̥] is reported almost exclusively before rounded vowels such as[o] and[y].
^Rangelov, Tihomir (2019)."The bilabial trills of Ahamb (Vanuatu): Acoustic and articulatory properties"(PDF). In Calhoun, S.; Escudero, P.; Tabain, M.; Warren, P. (eds.).Proceedings of the 19th International Congress of Phonetic Sciences, Melbourne, Australia 2019. Canberra: Australasian Speech Science and Technology Association. pp. 1292–1296.
^Lev, Michael; Stark, Tammy; Chang, Will (2012)."Phonological inventory of Oro Win".The South American Phonological Inventory Database (version 1.1.3 ed.). Berkeley: University of California: Survey of California and Other Indian Languages Digital Resource.
