Gbanu has 14 vowels, oral /ieɛaɔou/ and nasal /ĩẽɛ̃ãɔ̃õũ/. Syllables may be maximally CVN, where N is /m/ or /n/. There are four tones on CV syllables, high, low, rising, and falling. Words have six tone patterns, those four plus dipping (falling–rising) and peaking (rising–falling).
Vowels
Front
Front, Nasal
Back
Back, nasal
Close
i
ĩ
u
ũ
Close-mid
e
ẽ
o
õ
Open-mid
ɛ
ɛ̃
ɔ
ɔ̃
Open
a
ã
Tones
Tone
Rising
High
Low
Falling
Consonants
m
n
j~ɲ
w~ŋm
mb
nd
ŋɡ
ŋmɡb
ɓ~ˀm
ɗ~ˀn
p
t
k
kp
ʔ
b
d
ɡ
ɡb
f
s
h
v
z
nz
l
Intervocallically, the only voicing distinction that is maintained is /s,z/; otherwise only voiceless oral stops and fricatives occur between vowels.
Nasal consonants lightly nasalize surrounding vowels, and nasal vowels, including those triggered by nasal consonants, nasalize the glottalized consonants. The approximants /jw/ do not occur with nasal vowels, and so may not be phonemic; /j~ɲ/,/w~mŋ/ may be posited as the underlying phonemes.