A small number of documents preserved in Dunhuang contain an undeciphered language that has been called Old Zhangzhung, but the identification is controversial.
[2] Martin identifies the importance of this scripture for studies of the Zhangzhung language:For students of Tibetan culture in general, the mDzod phug is one of the most intriguing of all Bön scriptures, since it is the only lengthy bilingual work in Zhang-zhung and Tibetan (some of the shorter but still significant sources for Zhang-zhung are signalled in Orofino 1990).
Guillaume Jacques (2009) rebuts earlier hypotheses that Zhangzhung might have originated in eastern (rather than western) Tibet by having determined it to be a non-Qiangic language.
[8][9] This identification has been accepted by Takeuchi Tsuguhito (武内紹人), who called the language "Old Zhangzhung" and added two further manuscripts.
[11] However, David Snellgrove, and more recently Dan Martin, have rejected Thomas's identification of the language of these texts as a variant of Zhangzhung.