On tense and aspect in the Gaxi Horpa verb

Horpa is a little-studied language cluster in Sichuan falling under the Rgyalrongic subgroup in Sino-Tibetan. This study is a first attempt to explicate the verbal tense-aspect system of Gexi, a variety of Central Horpa in the Horpa language cluster. Conservative Rgyalrongic languages generally utilize a tripartite tense-aspect system with an aspectual (perfective vs. imperfective) distinction marked by prefixes, and a tense distinction marked by means of stem alternation. The Gexi tense-aspect system deviates drastically from the pan-Rgyalrongic norm, owing to a number of striking innovations it has undergone: (a) a sweeping reduction of stem variation leading to atrophy of tense-marking via stem alternations; (b) transformation of the pan-Rgyalrongic perfective structure into an anterior (relative past) verb form and development of the prefix da- into a general anterior prefix, often carrying an extended resultative marking function; (c) innovation of a periphrastic imperfective and a related durative imperfective. The important morphological innovations identified in this article appear to be inherently motivated as well as induced from contact with the locally dominant Tibetan language.