The fall and rise of the phoneme /r/ in Eastern Kiranti: sound change in Tibeto-Burman

The Kiranti languages are spoken in eastern Nepal and western Sikkim. What I call Eastern Kiranti in this article includes the languages Limbu, Yakkha, Yamphe, Yamphu, Lohorung and Mewahang. Further study will probably demonstrate that other languages spoken to the east of the SĀlpĀ watershed, such as Sam, underwent the same developments described here and must also be included in Eastern Kiranti. The autonyms used by the Limbus, Yakkha, Yamphe, Yamphu and Lohorung are indicative of a close historical relationship between them. The Limbu call themselves Yakthuŋba; the Yakkha call themselves Yakkha; and the Yamphe, Yamphu and Lohorung refer to their language as Yakkhaba.