Dialects
As the language is in a diglossic situation with standard Thai, dialects of the Lao language in Thailand share several features that set them apart from standard Lao: the adoption of Thai neologisms, code-switching between Thai and Lao, and influences on grammar and tone distribution which make certain standard Lao words and manners of speaking seem archaic or obsolete. However, dialectal isoglosses mirror the population movements from modern-day Laos into the Isan region and can be matched to those in Laos.
| Dialect | Lao Provinces | Thai Provinces | |
| Vientiane Lao (ภาษาลาวเวียงจันทน์) | Vientiane, Vientiane Capital Prefecture, Bolikhamsai | Nong Bua Lamphu, Chaiyaphum, and parts of Nong Khai, Yasothorn, Khon Kaen, and Udon Thani. | |
| Northern Lao (ภาษาลาวเหนือ) | Luang Prabang, Sainyabuli, Oudomxay. | Loei and parts of Udon Thani and Khon Kaen.*1 | |
| Northeastern Lao/Tai Phuan (ภาษาลาวตะวันออกเฉียงเหนือ/ภาษาไทพวน) | Xiangkhoang and Houaphanh. | Parts of Sakon Nakhon, Udon Thani.*2 | |
| Central Lao (ภาษาลาวกลาง) | Savannakhet and Khammouan. | Mukdahan and parts of Sakon Nakhon and Nong Khai. | |
| Southern Lao (ภาษาลาวใต้) | Champasak, Salavan, Sekong, and Attapeu. | Ubon Ratchathani, Amnat Charoen, and parts of Yasothorn, Buriram, Si Sa Ket, Surin and Nakhon Ratchasima*3 | |
| Western Lao (ภาษาลาวตะวันตก) | *4 | Kalasin, Maha Sarakham, and Roi Et. |
- (1) Also spoken in large parts of Uttaradit Province and Phitsanulok which are outside the Isan region.
- (2) Sometimes considered a separate language, as it is traditionally spoken by Tai Phuan tribal members, a closely related but distinct Tai group. Also spoken in a few small and scattered Tai Phuan villages in Sukhothai, Uttaradit, and Phrae.
- (3) Gives way to Northern Khmer in Si Sa Ket, Surin, and Buriram, and to Khorat Thai
- (4) Western Lao dialect is not spoken in Laos.
Read more about this topic: Isan Language