F0 of the verbal nasal prefix in Medumba

Both tone-bearing unit (TBU) and non-TBU syllables can exist in a tonal language [Roberts 2003, Cahiers voltaïques/Gur Papers 6, 95]. The verbal nasal prefix bears a high tone in many Bamileke languages [Voorhoeve 1974, Stud. Afr. Ling. 5: 205]; in Medumba, however, anecdotal evidence suggests that the nasal prefix may be a non-TBU [Keupdjio 2018, PC] in which case it cannot bear a high tone. The present study investigates the F0 contour of the verbal N-prefix and its surrounding TBUs (e.g., vowels in the preceding auxiliary verb and the following main verb) in various contexts in Medumba. Acoustic results show that the F0 contour of the nasal prefix itself is largely determined by the F0 trend of the preceding vowel, and no F0 change is observed at the onset of the nasal prefix, confirming that the verbal N-prefix is a non-TBU in Medumba. However, the nasal prefix appears to induce a raised F0 at the onset of the following TBU, indicating that, although the N-prefix itself does not express tone, it nevertheless “bears” a high tone. Implications for theories of TBUs will be discussed.