 However it could potentially include six, or even twelve vowels if accounting for the contrast between long and short vowels.According to research by Wichmann and later modified by Reilly, the vowels of this language "have a non-phonemic nasal counterpart, usually only realized in the presence of an inflectional nasal autosegment...

Vowels
ɨ, u, ɛ, ɔ, a

Vowel Phonemes

"Long and short vowels are also contrastive in lexical representations as is evident from the following minimal pair[s]