in the development of lingua francas, a cycle which leads to mixed and creolised languages, language shifts, linguistic discontinuities and ethnic mixing. It is estimated that Austroasiatic languages were present even as late as 4th-5th centuries CE, which is also supported by paleographic evidence from the Kamarupa inscriptions. The heavy creolisation occurred when Boro–Garo emerged as the lingua franca'' of the Tibeto-Burman and Austroasiatic populations of pre-Kamarupa, Kamarupa and post-Kamarupa kingdoms and polities of Assam, a proposition that other linguists find compelling, and that the prevalence of the Boro–Garo is attributed to language shifts, not population replacement. Some of the Boro–Garo speaking communities such as the matrilineal and uxorilocal Garo, Rabha, and to some extent Koch still retain cultural features that are found among Austroasiatic speakers and which are not found among other Tibeto-Burman speakers. Genetic studies too have shown that the Tibeto-Burman communities of Northeast India harbour significant population that were originally Austroasiatic speaking—for example, genetic studies show presence of O2a-M95, a haplogroup associated with AA populations, among the Garos. Groups Boro The Boro people, also called Bodo, are found concentrated in the duars regions, north of Goalpara and Kamrup. The origin of Kachari term was unknown to Boro themselves, but known to others. They call themselves as Boro, Bada, Bodo, Barafisa. Barafisa translated as Children of the Bara (the great one). Mech The Mech are found in both Assam and Bengal. Hodgson (1847) wrote as "Mech is name imposed by strangers. This people call themselves as Bodo. Thus, Bodo is their proper designation" They speak mainly the Boro language J.D Anderson wrote, "In Assam proper Hindus call them Kacharis, In Bengal they are known as Meches. Their own name for the race is Boro or Bodo." Dimasa Dimasas have a ruling clan among themselves who are termed as Hasnusa. Some Dimasa scholars opined that they were also known as Hasnusa at some point of time in History. Chutia Among Chutias, Burok means noble/great men. The Chutias who were thought to be healthy and strong was termed as Burok and took up the administrative and military roles in the Chutia kingdom. Even the Matak king Sarbananda Singha belonged to the Burok Chutia clan. Surnames like Bora, Borha, Borua have their origins in the Chutia kingdom and are related to Bara/Bodo/Buruk. There is mention of Manik Chandra Barua, Dhela Bora, Borhuloi Barua as commanders of Chutia army. Moran The Morans