Editing Mongolian language (section)

==== ATR harmony ====
[[File:Mongolian vowel harmony Venn diagram.svg|thumb|Vowel harmony in Mongolian]]
Mongolian divides vowels into three groups in a system of [[vowel harmony]]:

:{| class="wikitable" style="text-align: center;"
!
! +ATR ("front")
! −ATR ("back")
! Neutral
|-
|IPA
| {{IPA|/e, u, o/}}
| {{IPA|/a, ʊ, ɔ/}}
|{{IPA|/i/}}
|-
|Cyrillic
|э, ү, ө
|а, у, о
|и, ы and й
|-
|Romanization
|e, ü, ö
|a, u, o
|i
|}

For historical reasons, these have been traditionally labeled as "front" vowels and "back" vowels, as /o/ and /u/ developed from /ø/ and /y/, while /ɔ/ and /ʊ/ developed from /o/ and /u/ in Middle Mongolian. Indeed, in Mongolian [[romanization]]s, the vowels {{IPA|/o/}} and {{IPA|/u/}} are often conventionally rendered as {{angle bracket|ö}} and {{angle bracket|ü}}, while the vowels {{IPA|/ɔ/}} and {{IPA|/ʊ/}} are expressed as {{angle bracket|o}} and {{angle bracket|u}}. However, for modern Mongolian phonology, it is more appropriate to instead characterize the two vowel-harmony groups by the dimension of tongue root position. There is also one neutral vowel, {{IPA|/i/}}, not belonging to either group.

All the vowels in a non[[Compound (linguistics)|compound]] word, including all its suffixes, must belong to the same group. If the first vowel is −ATR, then every vowel of the word must be either {{IPA|/i/}} or a −ATR vowel. Likewise, if the first vowel is a +ATR vowel, then every vowel of the word must be either {{IPA|/i/}} or a +ATR vowel. In the case of suffixes, which must change their vowels to conform to different words, two patterns predominate. Some suffixes contain an archiphoneme {{IPA|/A/}} that can be realized as {{IPA|/a, ɔ, e, o/}}; e.g.
*{{IPA|/orx/}} 'household' + {{IPA|-Ar}} (instrumental) → {{IPA|/orxor/}} 'by a household'
*{{IPA|/xarʊɮ/}} 'sentry' + {{IPA|-Ar}} (instrumental) → {{IPA|/xarʊɮar/}} 'by a sentry'

Other suffixes can occur in {{IPA|/U/}} being realized as {{IPA|/ʊ, u/}}, in which case all −ATR vowels lead to {{IPA|/ʊ/}} and all +ATR vowels lead to {{IPA|/u/}}; e.g.
*{{IPA|/aw/}} 'to take' + {{IPA|-Uɮ}} (causative) → {{IPA|/awʊɮ/}}

If the only vowel in the word stem is {{IPA|/i/}}, the suffixes will use the +ATR suffix forms.<ref>Svantesson ''et al.'' (2005): 43–50.</ref>