Editing Osage language (section)

===Vowels===

====Basic vowels====
Osage has five plain [[vowel]]s:

{|class="wikitable"
! rowspan="2" |
! colspan="2" |[[Front vowel|Front]]
! rowspan="2" |[[Central vowel|Central]]
! rowspan="2" |[[Back vowel|Back]]
|-
![[Unrounded vowel|<small>Unrounded</small>]]!![[Rounded vowel|<small>Rounded</small>]]
|- align="center"
![[Close vowel|Close]]
|{{IPA link|i}} || colspan="2" |{{IPA link|y}} ~ {{IPA link|ʉ}}||
|- align="center"
![[Mid vowel|Mid]]
| colspan="2" |{{IPA link|ɛ}}|| ||{{IPA link|o}}
|- align="center"
![[Open vowel|Open]]
| colspan="2" | || colspan="2" |{{IPA link|ə}} ~ {{IPA link|ɑ}}
|}
These are written {{angle bracket|i u e o a}}. 

{{IPA|/u/}} varies between central and front, {{IPA|[ʉ ~ y]}}, and frequently unrounds to {{IPA|/i/}}. It is especially far front {{IPA|[y]}} following a velar obstruent and when it is near a front vowel with no intervening obstruent. It most commonly conflates with {{IPA|/i/}} following ''ð'' and ''n''.

Usually in fast speech, unstressed /a/ is pronounced {{IPA|[ə]}}.<ref>Quintero, 2009, p.xv</ref> This occurs after a stressed syllable, or at the end of a word. For example: {{IPA|céska [tsɛ́skə]}} 'cow', {{IPA|tóa [tóə]}} 'this one'.

====Nasalized vowels====
There are three vowels that carry this feature: {{IPA|[ɑ̃] [ĩ] [õ]}}. It is quite common for nasalized {{IPA|[ɑ̃]}} to become a nasal {{IPA|[õ]}} and vice versa. Non-nasalized vowels can be heard as nasalized as well. In general, vowels tend to become nasalized adjacent to another nasal vowel or consonant when there is no intervening obstruent. On the other hand, final nasal vowels tend to become oral. However, nasal vowels are always short, regardless of their position. 
Examples: {{IPA|[ʃímĩʒɛ]}} 'girl' and {{IPA|[paˑɣõ]}} 'mountain'

====Vowel clusters and long vowels====
According to Hans Wolff<ref name=article>{{cite journal|last=Wolff|first=Hans|title=Osage I: Phonemes and Historical Phonology|journal=International Journal of American Linguistics|date=April 1952|volume=18|issue=2|pages=63–68|doi=10.1086/464151|s2cid=145019201}}</ref> (65), common Osage vowel clusters are:
*iu {{IPA|[iü]}} for example: niuʒõ 'Neosho River'
*íe {{IPA|[íɛ]~[íi]}} for example: wíe 'I'
*íĩ {{IPA|[íĩ]}} for example: kasíĩte 'tomorrow'
*iuĩ {{IPA|[üĩ]}} for example: ékiuĩka 'don't'
*éa {{IPA|[ɛ́a]~[ɛ́ə]}} for example: cʼéaðe 'I killed him'
*aĩ {{IPA|[ɛ̃]}} for example: hówaĩke 'where?'
*óa {{IPA|[óə]}} for example: tóa 'this one'

Vowel length is important in Osage, but it is hard to perceive and has a good deal of variation. For example, long vowels are often reduced to short ones when they are not accented.<ref name="Quintero, 2009, p.xvi">Quintero, 2009, p.xvi</ref> Quintero took long vowels to be the underlying form in such situations. There is not enough information to specify exactly how the accent system works in Osage, and there is still uncertainty about Osage vowel length.

Oral vowels are long before non-stop consonants and in final stressed position. When they are unstressed in final position, they are always short.

Lengthening of short vowels often occurs in questions.<ref name="Quintero, 2009, p.xvi">Quintero, 2009, p.xvi</ref>
:Example: {{IPA|/ʃkó̃ʃta/}} 'you want' becomes {{IPA|[ʃkó̃õʃta]}}?

Long vowels also arise when ð is omitted between identical vowels.<ref name="Quintero, 2009, p.xvi"/>

:Example: ðakʼéwaða 'be kind to them' may become ðakʼéwaa.

When e(e) changes to a(a), an immediately preceding c is often replaced by t (thought not always)<ref>Quintero, 2009, p.xvii</ref>

:Example: océ 'look for, hunt for' becomes otá 'look for it!'

====Diphthongs====

The vowel sequences {{IPA|/aĩ/}} {{IPA|/eĩ/}} {{IPA|/oĩ/}} and {{IPA|/ai/}} are almost certainly{{According to whom|date=February 2025}} diphthongs.{{citation needed|date=March 2019}} The [[Osage script]] has letters to represent each of the diphthongs.