霍尔语群属于汉藏语系羌语支嘉戎语组，包括数种互不通话的独立语 言。四川甘孜州丹巴县东谷上半乡使用上东谷话，属于一种独特的中 部霍尔语方言。上东谷话的特点是正常声与弛声两种发声态呈现音位 对立，除区别词义外，还具有体现动词词干交替等形态功能。弛声的 来源尚不完全清楚，但其中一部分弛声在词汇与形态交替上与其他霍 尔语的低调或送气清擦音对应，应属古霍尔语存古音韵特征。上东谷 话的弛声有助于阐释本语群声调与送气交替的起源以及界定方言间 的谱系关系，是极有研究价值的语音现象。
Horpic denotes a cluster of little-explored languages under the Rgyalrongic subgroup of Qiangic in Sino-Tibetan. Upper Donggu, spoken in Rongbrag County of Dkarmdzes Prefecture, is a previously unknown dialect of Central Horpa, a major language within Horpic. Upper Donggu makes a phonemic distinction between modal and slack phonation. This remarkable feature not only contrasts lexical meanings, but also plays a role in verb-stem and other morphological formations. Sorting out the origins of slack phonation in Upper Donggu is still a daunting task, but partial correspondences in vocabulary and inflectional morphology can be established between Upper Donggu slack syllables and syllables in other Central Horpa varieties bearing low tone or voiceless aspirated fricative onsets. This suggests that phonation in Upper Donggu is a conservative feature that provides valuable clues to the origin of contrastive tone and fricative aspiration in Horpic, and also to the internal ramifications of this important Rgyalrongic subgroup.