The lowlands of Bangladesh form the eastern half of the ethno-linguistic region of Bengal and the Bengali language is spoken by the majority of the country's inhabitants. There are also some Eastern Indic language varieties, which are variously classified either as dialects of Bengali or separate but closely related languages. They can be thought of forming a dialect continuum.
Bengali branch:
* Bengali proper: spoken all over the country.
* Chittagonian: Spoken in the South–East region of Chittagong, it is often considered to be a dialect of Bengali, but both languages are largely mutually unintelligible.
* Sylheti: Spoken by Sylhetis in the North–East region of Sylhet.
* Hajong: Originally a Tibeto-Burman language that has shifted over time to an Indic language.
* Marma: Originated from Tibeto-Burman language and mother tongue of Marma ethnic people.
* Rohingya: Spoken in Arakan State, Burma and by refugees from that region, currently living in Bangladesh's Chittagong Division. It is also often called Arkani by native speakers.
* Tangchangya: Tanchangya is an Indo-Aryan language spoken by the Tanchangya people of Bangladesh. It is closely related to Chakma.
Bihari: Spoken primarily by the refugees from Bihar State, India.
Non-Indo-Aryan languages
The indigenous languages of the region are members of the Austroasiatic, Dravidian and Tibeto-Burman families. Most of these languages are spoken in mountainous areas.
While the more widely spoken and better-known Austroasiatic languages are spoken in Southeast Asia, smaller languages of that family are spoken by indigenous communities of northern and eastern Bangladesh.
Khasi: also a major language of Meghalaya State, India
The mountainous areas along the northern and eastern edges of the Indian Subcontinent are inhabited primarily by speakers of Tibeto-Burman languages. Indigenous Tibeto-Burman-speaking communities are found through the northern, eastern, and especially the southeastern parts of Bangladesh.
English is used marginally in the judiciary. Before the commencement of the Bengali Language Implementation Act, 1987, English had a considerable presence in official affairs, but since 1987 the usage of English has waned significantly in government. Due to the British colonization of the country, English is still a widely spoken and commonly understood language in Bangladesh. English is taught as a compulsory subject in all schools, colleges and universities, and is often used secondarily in the higher tier of the judiciary. However, there are English medium education system in Bangladesh. The British Council Bangladesh offers English language courses. During the colonial period, laws were written in English.
Arabic was an official language ever since the territory of the modern statePeople's Republic of Bangladesh became a part of the Bengal Sultanate. However some disagree and believe the presence of Arabic came before during the Delhi Sultanate. Arabic is used in many Muslim congregations such as the weekly Jumu'ah Salah in which a sermon is given in Arabic in addition to Bengali. In the Constitution of Bangladesh, there are two references to Arabic to in the introduction and Part I of the constitution. The document begins with the Arabic phrase بِسْمِ اللهِ الرَّحْمٰنِ الرَّحِيْمِ which is translated as “In the name of Allah, the Beneficent, the Merciful”. Article 2A declares that Islam is the state religion of the republic. Arabic is the religious language of Muslims. The Quran, Sunnah, Hadith and Muslim theology is taught in Arabic with Bengali translation. The Bangladeshi diaspora living in the Middle East has further increased the number of people who can speak Arabic in Bangladesh. Arabic is taught as a religious language in mosques, schools, colleges, universities and madrassahs as well as in tradition Bengali Muslim households. Arabic is an obligatory subject in the Madrasah education of Bangladesh. A majority of Bangladesh's Muslim population has had some form of formal or informal education in the reading, writing and pronunciation of the Arabic language as part of their religious education.
Persian
— Banglapedia
From ancient times Bengal and Persia had been in contact with each other. There were many trading posts around coastal Bengal. As people converted to Islam, they became acquainted with Arabic scriptures, as well as with Persian, the language of the Sufi preachers. The influence of the language spread rapidly after it gained the status of court language and it was the official for over 600 years.
Urdu
was an official language in post-partition 1947 to 1971. It is still spoken by some refugees from Bihar and Uttar Pradesh, and in Old Dhaka. They are also living in other parts of Bangladesh.
