Eastern Indo-Aryan languages
The Eastern Indo-Aryan languages, also known as Māgadhan languages, are spoken throughout the eastern region of the Indian subcontinent, which includes Bihar, Uttar Pradesh, Jharkhand, Bengal region, Tripura, Assam, and Odisha; alongside other regions surrounding the northeastern Himalayan corridor. Bengali is official language of Bangladesh and the state of West Bengal, Tripura and the Barak Valley of Assam while Assamese and Odia are the official languages of Assam and Odisha, respectively. The Eastern Indo-Aryan languages descend from Abahattha, which descends from Magadhan Apabhraṃśa and ultimately from Magadhi Prakrit.
Classification
The exact scope of the Eastern branch of the Indo-Aryan languages is controversial. All scholars agree about a kernel that includes the Odia cluster and the Bengali–Assamese languages, while many also include the Bihari languages. The widest scope was proposed by Suniti Kumar Chatterji who included the Eastern Hindi varieties, but this has not been widely accepted.When the Bihari languages are included, the Eastern Indo-Aryan languages fall into four language groups in two broader categories:
Western Magadhan
- Bihari
- *Bhojpuri
- **Caribbean Hindustani
- * Magahi
- **Khortha
- * Maithili
- **Bajjika
- **Angika
- **Central Maithili
- **Eastern Maithili
- **Thēthi
- **Jolaha
- **Kisan
- *Sadanic
- **Nagpuri
- **Kurmali
- *Unclassified Bihari
- **Tharuic
- ***Chitwania Tharu
- ***Dangaura Tharu
- ****Dangaha
- ***Sonha
- ***Kathariya Tharu
- ***Kochila Tharu
- ****Western Kochila
- ****Central Kochila
- ****Eastern Kochila
- ***Rana Tharu
- ***Buksa
- ***Musasa
- **Majhi
- **Kumhali
- **Kuswaric
- ***Danwar
- ****Dewas Done Danuwar
- *****Dewas Rai
- *****Done Danuwar
- ****Kochariya-East Danuwar
- *****East Danuwar
- *****Kochariya
- ***Bote-Darai
- ****Bote
- ****Darai
Eastern Magadhan
- Bengali–Assamese:
- * Gauda-Banga
- ** Bengali
- *** Bangali
- **** Dhakaiya kutti Bengali
- **** Mymensinghi Bengali
- *** Manbhumi
- *** Rarhi
- *** Barendri
- ** Bishnupriya Manipuri
- ** Chakma
- ** Chittagonian
- ** Noakhali
- ** Rohingya
- ** Sylheti
- ** Tanchangya
- ** Thar
- * Kamarupic:
- **Eastern Kamarupi
- *** Assamese
- ****Eastern Assamese
- ****Central Assamese
- **** Kamrupi
- **** Dehan
- *** Nagamese
- *** Nefamese
- **Western Kamarupi
- *** KRDS lects
- ****Kamtapuri
- **** Rangpuri
- **** Surjapuri
- **** Goalpariya
- **** Rajbanshi
- *** Hajong
- Oriya languages
- * Odia
- **Baleswari
- **Singhbhumi
- ** Kataki
- **Sundargadi
- **Kalahandia
- **Ganjami
- * Bodo Parja
- * Bhatri
- *Desia
- * Reli
- *Sambalpuri
- * Kupia
- Halbic:
- * Halbi
- **Adkuri
- **Bastari
- **Chandari
- **Gachikolo
- **Govari
- **Kawari
- **Kunbi
- **Mahari
- **Muri
- **Sundi
- * Kamar
- * Bhunjia
- * Nahari
Features
| Case | Bengali | Assamese | Odia | Rajbangshi | Surjapuri | Maithili | Bhojpuri | Tharu | Sylheti |
| Instrumental | -t̪e, -ke d̪ie | -e, -er-e, di, -e-di | -e, -re, -d̪ei | -d̪i | sɛ | -e,e˜, sə˜, d̪ea | le, leka | -re, di | |
| Dative | -ke, -re | -k, -ɒk | -ku | -k, -ɔk | -k, -ɔk | -ke˜ | -ke | -hənə | -gu, -gur |
| Ablative | -t̪ʰeke | -pɒra | -u, -ru, -ʈʰaru, -ʈʰiru | -hat̪ɛ, t̪ʰaki | -sɛ | -sə˜, -k -karəne | se | -lagi, -tône | |
| Genitive | -r, -er | -r, -ɒr | -rɔ | -r, -ɛr | -r, -ɛr | -ker | -kæ | -ək | -r, -ôr |
| Locative | -e, -t̪e | -t, -ɒt | -re | -t̪, -ɔt̪ | -t̪, -ɔt̪ | e, me, -hi, -tə | -mə | -t, -ô |
Eastern Indo-Aryan languages display many morphosyntactic features similar to those of Munda languages, while western Indo-Aryan languages do not. It is suggested that "pre-Munda" languages may have once dominated the eastern Indo-Gangetic Plain, and were then absorbed by Indo-Aryan languages at an early date as Indo-Aryan spread east.