The origin of the reflexive prefix in Rgyalrong languages

In the Sino-Tibetan family, reflexivity is either not expressed in the verb, as in Chinese or Tibetan, or expressed by means of a "middle" marker, as in Dulong or Kiranti languages. Among the morphologically rich languages of this family, only Rgyalrong languages have distinct and unambiguous reflexive and reciprocal markers on the verb. This paper shows that the reflexive prefix in Rgyalrong languages has two possible origins. It could come from a fusion of the third person singular marker and the root meaning "self' or, alternatively, come from the free third person pronoun. Both hypotheses are compatible with our understanding of Rgyalrong historical phonology.