Paths to tone in the Tamang branch of Tibeto-Burman (Nepal) Martine Mazaudon Centre National de la recherche Scientifque, Paris We examine a phonological change in progress in Tamang-Gurung-Takali- Manangke (TGTM), a group of Tibeto-Burman dialects or languages of Nepal. Data from eight language varieties, fve of them studied frst-hand in the feld, are presented. Te phonological change studied is a modern-day instance of the tonal split which swept through the whole of Asia in the Middle Ages: Chinese, Vietnamese, Tai and many less known languages underwent a merger of two of their series of initials (most commonly voiced/voiceless), resulting in a split of their tonal systems. Hypotheses about the modalities of implementation of this change have been ofered, but modern day traces of intermediate stages are very limited. Te languages of the Himalayas are situated at the geographical and chonological end of this wave so that the change is still in progress. In all the TGTM dialects studied here, the tonal split is phonologically completed, but traces of previous distinctions in manner of articulation and in phonation type survive, ofering possible models for previously unobserved intermediate stages in tonogenesis. 1 From the similarities and diferences observed between the dialects, some conclusions can be drawn. In diachrony, the common passage by a breathy stage between consonant-borne voice contrasts and tone, which has been proposed for the pan-Asian tonal split, is corroborated for all TGTM languages. But afer the phonologization of tone, the degree, modality and factors of retention of the old features of voice and breathiness difer from dialect to dialect. Building on the repetition of distinct but similar changes, a tentative “law” is proposed for the evolution of breathiness, emphasizing the interplay of phonetic and phonological constraints in historical development: in a language where breathiness is used . We gratefully acknowledge the contribution of the following people either for discussion and references, or for comments and criticism on an earlier version of this paper: Juliette Blevins, Jerry Edmondson, John Esling, Michel Ferlus, Bert Remijsen, Laurent Sagart, and two anonymous reviewers. Special thanks for repeated discussions and overall reading of the paper to Boyd Michailovsky and Alexis Michaud. Tey of course are not responsible for remaining infelicities. We also thank Jean-Michel Roynard for the map, and he and Alexis Michaud for the figures. Published in The Dialect Laboratory: Dialects as a testing ground for theories of language change, ed. by G. de Vogelaer & G. Seiler, 139-77. Amsterdam/Philadelphia: John Benjamins.