Bengali is an Indo-Aryan language, described in the survey edited by George Cardona and Dhanesh Jain, and it is spoken by well over two hundred million people in Bangladesh and in the Indian state of West Bengal. Its religious literature therefore belongs to a Muslim majority country and a Hindu majority state at the same time, and the Muslim Bengali tradition, including the punthi literature and a large body of devotional song, is often left out of accounts written from one side of that border.
Nineteenth century Calcutta made Bengali a language of religious reform. The Brahmo Samaj, founded by Ram Mohan Roy in 1828, argued in Bengali for a monotheistic Hinduism without images, and against sati, which was prohibited by regulation in the Bengal Presidency the following year. Ramakrishna, who taught in Bengali and in parables, and Vivekananda, who carried a version of that teaching abroad, both came out of the same setting.
Language itself then became a political and religious question. The movement to defend Bengali against the imposition of Urdu in Pakistan produced deaths in Dhaka in 1952 and, in time, the independence of Bangladesh, and the day is now observed internationally as a mother language day.