On the Ngbugu vowel system

Previous researchers have posited asymmetric oral vowel systems for Ngbugu and
other Banda languages. The present analysis shows that Ngbugu has a symmetric
ten-vowel system which includes one interior vowel /ə/ and lacks vowel harmony.
It also supports and refines Boyeldieu & Cloarec-Heiss’s (2001) proposed
Proto-Banda vowel system. The affinities of the resulting proto vowel system to those
of nearby languages could facilitate the comparison of vowel systems across the
region in order to test hypotheses about shared inheritance or borrowing. Possible
explanations for the lack of vowel harmony are suggested.