I have been able to use two sources: first and foremost the Denden manuscripts from the collection in the British Museum, which were obtained in the 19th century by Dr. George Macartney from Islam Akhun in the Tarim basin (Hopkirk 1986: 98-104). The Institute of Oriental Studies of the Russian Academy of Sciences in St. Petersburg has a number of highly important manuscripts, obtained by the intrepid Russian explorer Nikolai Petrovsky from the same source, amongst which the only known indigenous grammar. The manuscript data is especially important because the documents span nearly fourteen centuries and all mentioned Charyan languages, and a few other languages from Andal.

Secondly, in the cellar of Duke of Islingtons library at Twincaster University, a sack filled with a large number of untitled tapes was found. Upon examination, it turned out that these tapes contain recordings of spoken Denden, Southern Colloquial, Northern Colloquial and a few other, as yet unidentified languages. Unfortunately, it is not known who made the recordings, when they were made, and exactly how and when they appeared in the library.

Of course, the theory has been advanced that these tapes are a hoax, meant to support the oft-doubted claims of the Akhun manuscripts. But the material is far to extensive and consistent to allow of this interpretation, and the only conclusion can be that, no matter how mysterious the origin, all Denden material is genuine and must be studied.