Its manner of articulation is trill, which means it is produced by directing air over an articulator so that it vibrates. In most instances, it is only found as the trilled release of a prenasalized stop.
The Knorkator song "[Buchstabe]" (the actual title is a glyph) on the 1999 album Hasenchartbreaker uses a similar sound (though linguolabial instead of bilabial) to replace "br" in a number of German words (e.g. [ˈʙaːtkaɐ̯tɔfəln] for Bratkartoffeln).
Phonemic according to Pavlík (2017) occurring before /u/ or as a syllabic consonant. [ʙ] is classified as an allophone of /u/ following a /p/, /b/, /t/ or /d/ in the phonemic analysis of Huáng (1992:673–674), and Yǐn (2016).[11] No bilabial trills are present in the phonemic analysis of Nishida (2013).
In many of the languages in which the bilabial trill occurs, it occurs only as part of a prenasalized bilabial stop with trilled release, [mbʙ]. That developed historically from a prenasalized stop before a relatively high back vowel like [mbu]. In such instances, the sounds are usually still limited to the environment of a following [u]. However, the trills in Mangbetu may precede any vowel and are sometimes preceded by only a nasal.
^ abcFoley, William A. (2018). "The Languages of the Sepik-Ramu Basin and Environs". In Palmer, Bill (ed.). The Languages and Linguistics of the New Guinea Area: A Comprehensive Guide. The World of Linguistics. Vol. 4. Berlin: De Gruyter Mouton. pp. 197–432. ISBN978-3-11-028642-7.
^Rangelov, Tihomir (2019), The bilabial trills of Ahamb (Vanuatu): acoustic and articulatory properties, University of Waikato
^ abCoupe, Alexander (2016), "Prestopped bilabial trills in Sangtam", Proceedings of the 18th International Congress of Phonetic Sciences, Glasgow, 10-14 August 2015.
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