Itsmanner of articulation istrill, 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 aprenasalized stop.
Phonemic according toPavlík (2017) occurring before/u/ or as asyllabic consonant. [ʙ] is classified as an allophone of/u/ following a/p/,/b/,/t/ or/d/ in the phonemic analysis ofHuáng (1992:673–674), andYǐn (2016).[11] No bilabial trills are present in the phonemic analysis ofNishida (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 highback 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[12] 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.
^See, e.g., among the numerous data of Robert G. McKee's "Concerning Meegye and Mangbetu’s bilabial trills," in Advances in Nilo-Saharan Linguistics: Proceedings of the 8th Nilo-Saharan Linguistics Colloquium, University of Hamburg, August 22–25, 2001, Doris L. Payne & Mechthild Reh (eds.), 181–189 (2007, Rüdiger Köppe Verlag, Cologne).
