Languages

Modern-day Arunachal Pradesh is one of the linguistically richest and most diverse regions in all of Asia,being home to at least 30 and possibly as many as 50 distinct languages in addition to innumerable dialects and subdialects thereof. Boundaries between languages very often correlate with tribal divisions—for example, the Apatani and Nyishi are tribally and linguistically distinct—but shifts in tribal identity and alignment over time have also ensured that a certain amount of complication enters into the picture—for example, the  Galo language is and has seemingly always been linguistically distinct from Adi, whereas the earlier tribal alignment of Galo with Adi i.e., "Adi Gallong" has only recently been essentially dissolved.

The vast majority of languages indigenous to modern-day Arunachal Pradesh belong to the Tibeto-Burman family.The majority of these in turn belong to a single branch of Tibeto-Burman, namely Abo-Tani language. Almost all Tani languages are indigenous to central Arunachal Pradesh, including moving from west to east the Nyishi, the Apatani, the Tagin, the Galo, the Bokar, the Adi, the Padam, the Pasi, and the Minyong. The Tani languages are noticeably characterised by an overall relative uniformity, suggesting relatively recent origin and dispersal within their present-day area of concentration. Most of the Tani languages are mutually intelligible with at least one other Tani language, meaning that the area constitutes a dialect chain, as was once found in much of Europe; only Apatani and Milang stand out as relatively unusual in the Tani context. Tani languages are among the better-studied languages of the region.

To the east of the Tani area lie three virtually undescribed and highly endangered languages of the "Mishmi" group of Tibeto-Burman: Idu, Digaru and Miju. A number of speakers of these languages are also found in Tibet. The  relationships of these languages, both amongst one another and to other area languages, are as yet uncertain. Further south, one finds the Singpho Kachin language, which is primarily spoken by large populations in Myanmar's Kachin State, and the Nocte and Wancho languages, which show affiliations to certain Naga languages spoken to the south in modern-day Nagaland.

To the west and north of the Tani area are found at least one and possibly as many as four Bodic languages, including Dakpa and Tshangla language; within modern-day India, these languages go by the cognate but, in usage, distinct designations Monpa and Memba. Most speakers of these languages or closely related Bodic languages are found in neighbouring Bhutan and  Tibet, and Monpa and Memba populations remain closely adjacent to these border regions.

Between the Bodic and Tani areas lie a large number of almost completely undescribed and unclassified languages, which, speculatively considered Tibeto-Burman, exhibit many unique structural and lexical properties that probably reflect both  a long history in the region and a complex history of language contact with neighbouring populations. Among them are  Sherdukpen, Bugun, Aka/Hruso, Koro, Miji, Bangru and Puroik/Sulung. The high linguistic significance these languages
is belied by the extreme paucity of documentation and description of them, even in view of their highly endangered status. Puroik, in particular, is perhaps one of the most culturally and linguistically unique and significant populations in all  of Asia from proto-historical and anthropological-linguistic perspectives, and yet virtually no information of any real  reliability regarding their culture or language can be found in print.

Finally, other than the Bodic and Tani groups, there are also certain migratory languages which are largely spoken by migratory and central government employees serving in the state in different departments and institutions in modern-day  Arunachal Pradesh. They are classified as Non-Tribal as per the provisions of the Constitution of India.

Outside of Tibeto-Burman, one finds in Arunachal Pradesh a single representative of the Tai family, spoken by tribes  like the Khampti and Singpho, which is closely affiliated to the Shan language of Myanmar's Shan State. Seemingly,  Khampti is a recent arrival in Arunachal Pradesh whose presence dates to 18th and/or early 19th-century migrations  from northern Myanmar.

In addition to these non-Indo-European languages, the Indo-European languages Assamese, Bengali, English, Nepali and  especially Hindi are making strong inroads into Arunachal Pradesh. Primarily as a result of the primary education system—in which classes are generally taught by Hindi-speaking immigrant teachers from Bihar and other Hindi-speaking parts of northern India, a large and growing section of the population now speaks a semi-creolized variety of Hindi as a mother tongue. Hindi acts as a lingua franca for most of the people in the state.Despite, or perhaps because of, the linguistic diversity of the region, English is the only official language recognised in the state.

The speakers of major languages of the state according to the 2001 census are Nyishi 208,337, Adi 193,379, Bengali 97,149,Nepali 94,919, Hindi 81,186, Monpa 55,428, Assamese 51,551, Wancho 48,544, Tangsa 34,231, Mishmi 33,522, Mishing 33,381,
Nocte 32,591, and Others 64,711.