I have conducted extensive research on endangered languages, sociolinguistics, historical linguistics, geolinguistics, language policy and phonetics/phonology in Southeast, East and South Asia over many years, especially on Tibeto-Burman languages, as well as on other languages of these areas and on varieties of English. I am a member of the editorial boards of eight international journals and monograph series, the author, co-author, editor or co-editor of over twenty books and five language atlases, several with translation and/or second and third editions and of numerous other publications.