All information on the Osage vowel and consonantal systems stems from Quintero's Osage Grammar (Quintero 2004: 16-42).
The Osage vowel system
|high||i||(u)||ĩ||u (ü [y])|
- u is high front rounded or high central rounded, in the latter case ü [y]
- there is high variation in the use of ã and õ; they are often interchangeable. My interpretation, which is consistent with at least Omaha-Ponca, a Degiha language too, is that the actual nasal sound is rather a nasal ɔ [ɔ̃], which is a vowel approximately between ã and õ. The transcription then, if one doesn't employ the IPA symbol ɔ̃, must choose between ã and õ.
The Osage consonantal system
Quintero considers underlying segments ph, th and kh which according to her never emerge on the surface; they are in parenthesis in the table.
- The voicing of z and ž is faint.
- The approximant r only occurs in the cluster br. In 1SG marked verbs, br occurs frequently, where in Quintero's interpretation r is an allophone of ð. There are also other occurrences of br, which Quintero calls "morphologically opaque"; e.g. brã 'smell, emanate an odour', íbrã 'have/get enough of', bráaska 'flat'.