Nsei language
Kenswei Nsei (Kensense), also Nsei or Mesing (Bamessing), is a Grassfields Bantu language of Cameroon.

Phonology

Consonants

Vowels

Tone
Nsei has both lexical and grammatical tone. There are at least two level tones (high, low, and possibly mid) and two contour tones (falling and rising).

References

Further reading

Ring languages
Languages of Cameroon