Ahom is a language of the Southwestern Tai group, brought to India by a group of people from Mau Lung, or Müng Mau (məŋ5 māu5 loŋ6 ‘country-Mau-large’ in Tai Phake), now on the China/Burma border to the north of Shan State, Myanmar. Ahom was spoken as the language of court and ritual in the Ahom kingdom and as a mother tongue by some portion of the multilingual population ruled by that kingdom, a population that is known to have included several Tibeto-Burman speaking groups that were in Assam before the arrival of the Ahoms.
The Ahom kingdom lasted from 1228, when the Tai prince Sukapha set up his kingdom in the Upper Brahmaputra valley, until 1824 when it was overthrown by the Burmese and then supplanted by British rule. From the earliest days of their settlement in Assam, the Ahoms intermarried with local people, both Tibeto-Burman and Indie speaking. This, combined with the fact that from at least the early sixteenth century, the Ahom court began to abandon its ancient Tai religious practice for Hinduism, led to a gradual decline in the use of Ahom as a spoken Tai language. It seems that by 1800, the language was little, if at all, used as a mother tongue.
Today, Tai language is not spoken as a mother tongue by the Tai Ahom people, but the language remains both in ritual and in the many manuscripts that survive.