There is no retroflexion in Assamese, nor is there any retroflexion in Nagamese or in any of the tribal languages that surround it. In other words, Assamese has just t, th, d, dh, n and r, which are alveolar t and d sounds, the same ones you hear in British and American English. The western border of Assam marks the unequivocal end of the retroflexion zone in South Asia.
