Acoustic properties of bilabial trills in Medumba


  • Kenneth S. Olson SIL International



bilabial trills, prenasalization, release, speech timing, Narrow Grassfields, Medumba


Olson (2022) claims that all bilabial trills in phonemic systems are releases of stops. They are either part of complex phonemes that involve stop-trill sequences, e.g. /pᴮ, bᴮ, ᵐbᴮ, tᴾ/, or they pattern as allophones of a compressed or fricative vowel following a stop, e.g. [pʙ̩, bʙ̩, tʙ̩]. Olson notes that the stop-trill phonemes behave as obstruents. I provide acoustic evidence for this claim. Previous studies indicate that the closure of /b/ is shorter than that of /p, ᵐb/ and that the oral portion of the closure of /ᵐb/ is very short (~30–40 ms). Likewise, it has been shown that the stop closure of /bᴮ/ is shorter than that of /pᴮ, ᵐbᴮ/ and that the oral portion of the stop closure of /ᵐbᴮ/ is very short (e.g. Olson 2023). For Medumba (Cameroon), we find similar patterning. The mean stop closure durations of /bᴮ, ᵐbᴮ/ are 137 ms (s.d. = 28, n = 58) and 192 ms (s.d. = 47, n = 28), respectively. The difference is very highly significant: t(37) = 5.79, p < 0.001 (one-tailed). The mean oral stop closure duration of /ᵐbᴮ/ is 26.6 ms (s.d. = 6.2, n = 28). The finding that stops with bilabial trill releases behave as obstruents is important, because elsewhere they have been categorized with /r/ assuming that they are sonorants.




How to Cite

Olson, Kenneth. 2024. “Acoustic Properties of Bilabial Trills in Medumba”. Proceedings of the Linguistic Society of America 9 (1): 5642.