|Region||Northwest Region, Cameroon|
|pʰ||Before /u/ in an open syllable.|
|β||Between vowels within a root.|
|k||k||Beginning of words and of roots within words, and after /ɴ̩/.||〈k〉|
|ʔ||Only C found at ends of words.||〈’〉|
|s||s||/ts/ after /ɴ̩/.||〈s〉|
|ʃ||ʃ||/tʃ/ after /ɴ̩/.||〈sh〉|
|N̩||m̩ n̩ ŋ̍||Homorganic with following C. Carries tone.||〈m〉, 〈n〉|
- py (mby), ly (ndy), ty, ky, ngy, my, kẅ, ngẅ (= /kʷj, ɡʷj/)
- pw (mbw), lw (ndw), tw, tsw, chw, shw, sw, zw, zhw, nw, nyw, ŋw
All noun and verb roots begin with a consonant; initial vowels are necessarily prefixes. Only /a, ɨ/ occur in prefixes or at the beginning of words, and only /ə/ occurs in suffixes. /ɨ, y/ do not occur at the ends of words.
All known long vowels may occur medially or at ends of words, none at the beginning, though long /ɛ, y/ are not attested. Long vowels are written double: aa, əə, ii, ‿ɨɨ, oo, uu. Diphthongs ie, iə, ʉə, ɨə, uə take a single tone.
Tones are high, mid, low, rising, falling. They are written as in IPA, apart from low, which is not written: á ā a ǎ â. Falling tone is largely confined to suffixes, and rising tone is rare, found only on a few nouns such as tǎ 'father'.
- The Pinyin Orthography Guide (Njeck Mathaus Mbah & Stephen C. Anderson, 2005)