Editing Isan language (section)

===Vowels===
The vowel structure of Isan is the similar as the central and southern Lao dialects of Laos. The vowel quality is also similar to Thai, but differs in that the two back vowels, [[close back unrounded vowel]] /ɯ/ and the [[close-mid back unrounded vowel]] /ɤ/, centralized as the [[close central unrounded vowel]] /ɨ/ and the [[mid central vowel]] /ə/ in some speakers, respectively, as well as in diphthongs that may include these sounds. To Thai speakers, Isan and Lao vowels tend to have a nasal quality.

In many cases, especially diphthongs with /u/ as first element is lengthened in Isan as it is in Standard Lao, so that the word ''tua'' which means 'body' ({{langx|th|ตัว}}, written the same in Isan) is pronounced {{IPA|/tua/}} in Thai but in Isan as {{IPA|/tuːa/}} in some dialects, similar to {{langx|lo|ຕົວ}}. The symbol '◌' indicates the required presence of a consonant, or for words that begin with a vowel sound, the 'null consonant' 'อ' or its Lao equivalent, 'ອ', which in words that begin with a vowel, represents the glottal stop /ʔ/. Short vowels that end with '◌ะ' or Lao '◌ະ' also end with a glottal stop.

Thai and Lao are both [[abugida]] scripts, so certain vowels are pronounced without being written, taking the form of /a/ in open syllables and /o/ in closed syllables, i.e., ending in a consonant. For example, the Khmer loan word ''phanom'' or 'hill' found in many place names in Isan is {{langx|tts|พนม}} or 'PH-N-M' but pronounced {{IPA|/pʰàʔ.no᷇m/}}, with 'PH' as the open syllable and 'N-M' as the closed syllable. In Lao orthography, inherited from Tai Noi, closed syllables are marked with a 'ົ' over the consonants and the /a/ of open syllables was unwritten, thus {{langx|lo|ພນົມ}} or 'Ph-N-<sup>o</sup>-M'. In current practice as a result of spelling reforms, all vowels are written out and in modern {{langx|lo|ພະນົມ}} or 'Ph-a-N-<sup>o</sup>-M' is more common thus modern Lao is no longer a true abugida.

{| class="wikitable" style="text-align:center;"
|+ Isan vowel distribution
|- style="font-weight:bold; vertical-align:middle; background-color:#EAECF0; color:#202122;"
! style="text-align:left;" | 
! [[Front vowel|Front]]
! [[Central vowel|Central]]
! [[Back vowel|Back]]
|- style="vertical-align:middle; background-color:#F8F9FA; color:#202122;"
! style="text-align:left;" | [[Close vowel|Close]]
| {{IPAslink|i}}
| {{IPAslink|ɨ}} ~ {{IPAslink|ɯ}}
| {{IPAslink|u}}
|- style="vertical-align:middle; background-color:#F8F9FA; color:#202122;"
! style="text-align:left;" | [[Mid vowel|Mid]]
| {{IPAslink|e}}
| {{IPAslink|ə}} ~ {{IPAslink|ɤ}}
| {{IPAslink|o}}
|- style="vertical-align:middle; background-color:#F8F9FA; color:#202122;"
! style="text-align:left;" | [[Open vowel|Open]]
| {{IPAslink|ɛ}}
| {{IPAslink|ä|a}}
| {{IPAslink|ɔ}}
|}

====Vowel length====
Vowels usually exist in long-short pairs determined by [[vowel length]] which is [[phoneme|phonemic]], but vowel length is not indicated in the RTGS romanization commonly used in Thailand or the BGN/PCGN French-based scheme commonly used in Laos. The Isan word romanized as ''khao'' can represent both {{langx|tts|เขา}} {{IPA|/kʰǎw/}}, 'he' or 'she', and {{langx|tts|ขาว}} {{IPA|/kʰǎːw/}}, 'white' which corresponds to {{langx|lo|ເຂົາ}} and {{langx|lo|ຂາວ}}, respectively, which are also romanized as ''khao''. In these cases, the pairs of words have the same tone and pronunciation and are differentiated solely by vowel length.

{| class="wikitable" 
|+ Isan Long-Short Vowel Pairs (Thai Script/Lao Pronunciation)
! colspan="4" | Long vowels
! colspan="4" | Short vowels
|-
| Thai
| IPA
| Lao
| IPA
| Thai
| IPA
| Lao
| IPA
|-
| colspan="4";|
| ◌ำ
| /am/
| ◌ຳ
| /am/
|-
| ◌า
| /aː/
| ◌າ
| /aː/
| ◌ะ, ◌ั, *{{ref|assumed|1}} 
| /aʔ/, /a/
| ◌ະ, ◌ັ
| /aʔ/, /a/
|-
| ◌ี
| /iː/
| ◌ີ 
| /iː/
| ◌ิ
| /i/
| ◌ິ 
| /i/
|-
| ◌ู
| /uː/
| ◌ູ
| /uː/
| ◌ุ
| /u/
| ◌ຸ
| /u/
|-
| เ◌
| /eː/
| ເ◌
| /eː/
| เ◌ะ, เ◌็
| /eʔ/, /e/
| ເ◌ະ, ເ◌ົ 
| /eʔ/, /e/
|-
| แ◌
| /ɛː/
| ແ◌
| /ɛː/
| แ◌ะ, แ◌็
| /ɛʔ/, /ɛ/
| ແ◌ະ, ແ◌ົ 
| /ɛʔ/, /ɛ/
|-
| ◌ื, ◌ือ 
| /ɯː/
| ◌ື 
| /ɯː/
| ◌ื
| /ɯ/
| ◌ຶ
| /ɯ/
|-
| เ◌อ, เ◌ิ 
| /ɤː/
| ເີ◌ 
| /ɤː/
| เ◌อะ
| /ɤʔ/
| ເິ◌ 
| /ɤʔ/
|-
| โ◌
| /oː/
| ໂ◌
| /oː/
| โ◌ะ, *{{ref|asssumed|2}}
| /oʔ/, /o/
| ໂ◌ະ, ◌ົ 
| /oʔ/, /o/
|-
| ◌อ
| /ɔː/
| ◌ອ◌, ◌ໍ
| /ɔː/
| เ◌าะ
| /ɔʔ/
| ເ◌າະ
| /ɔʔ/
|}
*{{note|assumed|1}} Unwritten in open syllables.
*{{note|asssumed|2}} Unwritten in closed syllables.

====Diphthongs====
{| class="wikitable" 
|+ Isan Diphthongs<br />(Thai Script/Lao Pronunciation)
! colspan="4" | Long vowels
! colspan="4" | Short vowels
|-
! Thai
! IPA
! style="width: 11em; | Lao
! IPA
! Thai
! IPA
! style="width: 11em; | Lao
! IPA
|-
| colspan="4"|
| ◌วำ{{ref|ThaiWam|3}} 
| /wam/
| ◌ວຳ 
| /uam/
|-
| ◌าย
| /aːj/
| ◌າຍ/◌າຽ{{ref|OldLao|2}}
| /aːj/
| ไ◌{{ref|long|1}}, ใ◌{{ref|long|1}}, ไ◌ย, ◌ัย
| /aj/
| ໄ◌{{ref|long|1}}, ໃ◌{{ref|long|1}}, ໄ◌ຍ{{ref|long|1}}<sup>,</sup>{{ref|OldLao|2}}/ໄ◌ຽ{{ref|OldLao|2}}, ◌ັຍ{{ref|OldLao|2}}/◌ັຽ{{ref|OldLao|2}} 
| /aj/
|-
| ◌าว 
| /aːw/
| ◌າວ 
| /aːw/
| เ◌า{{ref|long|1}}
| /aw/
| ເ◌ົາ{{ref|long|1}}
| /aw/
|-
| colspan="4";|
| ◌ิว
| /iw/
| ◌ິວ
| /iw/
|-
| เ◌ีย
| /ia/
| ເ◌ຍ/ເ◌ັຽ{{ref|OldLao|2}}, ◌ຽ◌
| /ia/
| เ◌ียะ
| /iaʔ/
| ເ◌ັຍ/ເ◌ັຽະ{{ref|OldLao|2}}
| /iaʔ/
|-
| ◌อย 
| /ɔːj/
| ◌ອຍ/◌ອຽ{{ref|OldLao|2}} /◌ຽ{{ref|OldLao|2}} 
| /ɔːj/
| rowspan="2" colspan="4";|
|-
| โ◌ย
| /oːj/
| ໂ◌ຍ/ໂ◌ຽ{{ref|OldLao|2}} 
| /oːj/
|-
| เ◌ือ, เ◌ือ◌ 
| /ɯa/
| ເ◌ືອ, ເ◌ືອ◌ 
| /ɯa/
| เ◌ือะ
| /ɯaʔ/
| ເ◌ຶອ
| /ɯaʔ/
|-
| ◌ัว, ◌ว◌
| /ua/
| ◌ັວ, ◌ວ◌, ◌ວາ, 
| /ua/
| ◌ัวะ
| /uaʔ/
| ◌ົວະ,
| /uaʔ/
|-
| ◌ูย 
| /uːj/
| ◌ູຍ/◌ູຽ{{ref|OldLao|2}}
| /uːj/ 
| ◌ຸย 
| /uj/
| ◌ຸຍ/◌ຸຽ{{ref|OldLao|2}} 
| /uj/
|-
| เ◌ว
| /eːw/
| ເ◌ວ 
| /eːw/
| เ◌็ว
| /ew/
| ເ◌ັວ
| /ew/
|-
| แ◌ว
| /ɛːw/
| ແ◌ວ 
| /ɛːw/
| rowspan="2" colspan="4";|
|-
| เ◌ย 
| /ɤːj/ 
| ເ◌ີຍ/ເ◌ີຽ{{ref|OldLao|2}} 
| /ɤːj/
|}
*{{note|long|1}} Considered long vowels for the purpose of determining tone.
*{{note|OldLao|2}} Archaic usage common in pre-1970s Lao.
*{{note|ThaiWam|3}} The Thai vowel 'ำ' is a short vowel. In Isan, it is diphthongized after /w/ into /uam/.

====Triphthongs====
{| class="wikitable" 
|+ Isan Triphthongs<br />(Thai Script/Lao Pronunciation)
!Thai
!IPA
!Lao
!IPA
|-
| เ◌ียว{{ref|long|1}}
| {{IPA|/iaw/}}
| ◌ຽວ{{ref|long|1}}
| {{IPA|/iaw/}}
|-
| ◌วย{{ref|long|1}}
| {{IPA|/uaj/}}
| ◌ວຍ/◌ວຽ{{ref|long|1}}<sup>,</sup>{{ref|OldLao|2}} 
| {{IPA|/uaj/}}
|-
| เ◌ือย{{ref|long|1}}
| {{IPA|/ɯaj/}}
| ເ◌ືວຍ{{ref|long|1}}/ເ◌ືວຽ{{ref|long|1}}<sup>,</sup>{{ref|OldLao|2}}
| {{IPA|/ɯaj/}}
|}
*{{note|long|1}} Considered long vowels for the purpose of determining tone.
*{{note|OldLao|2}} Archaic usage common in pre-1970s Lao.

====Tones====
{| class="wikitable"
|-----bgcolor="#eeeeee"
|+ Isan Tone Distribution (Khon Kaen-Roi Et)<ref>{{cite journal |last1=Hartmann |first1=J. |year=1971 |url=http://www.siamese-heritage.org/jsspdf/1971/JSS_068_1g_Hartmann_AlignmentOfDialectsInSouthwesternTai.pdf |title=A model for the alignment of dialects in southwestern Tai |archive-url=https://web.archive.org/web/20210418090250/http://www.siamese-heritage.org/jsspdf/1971/JSS_068_1g_Hartmann_AlignmentOfDialectsInSouthwesternTai.pdf |archive-date=2021-04-18 |journal=Journal of the Siam Society |volume=65 |issue=2 |pages=72–87 }}</ref>
||'''Tone Class'''||'''Inherent Tone'''||'''Mai ek ({{lang|th|อ่}})'''||'''Mai tho ({{lang|th|อ้}})'''||'''Long Vowel'''||'''Short Vowel'''
|----- bgcolor="#ffffff"
! High
|| Rising
|| Mid
|| Low
|| Low
|| Mid-low
|----- bgcolor="#ffffff"
! Middle
|| Low
|| High
|| Falling
|| Low
|| Rising
|----- bgcolor="#ffffff"
! Low
|| Falling
|| Mid
|| Mid-low
|| Falling
|| Low
|}