He specializes in Southeast Asian linguistics, particularly on comparative phonology and historical reconstruction. His main interests are in the genetic relationships of the languages of East/Southeast Asian areas and the linguistic implications on the (pre)history and cultures of the respective people. His major works include Proto-Kra (Berkeley: Linguistics of the Tibeto-Burman Area) and “Kra-Dai and Austronesian: Notes on the phonological correspondences and vocabulary distribution” (The peopling of East Asia: Putting together archaeology, linguistics, and genetics). His past experience includes a research visit at the National Museum of Ethnology, Osaka, in 2000-2001. He currently visits the Institute of Linguistics, Academia Sinica, for an investigation on the linguistic relationship between Tai and Chinese.