Hezhang Buyi is a previously undocumented Northern Tai language that has absorbed elements of an unknown Kra language, which has left its effect on the phonology, lexicon, and syntax of Hezhang Buyi. Comparisons with a Buyi dialect of Jichang Township, Zhijin County, Guizhou that I had documented indicate that Hezhang Buyi is most closely related to Buyi dialects spoken just to the southeast of Hezhang County. “Hezhang Kra,” the substrate language of Hezhang Buyi, was likely to have been part of an extensive dialect chain of Kra lects that would have been spoken from northern Vietnam up to as far north as southeastern Sichuan, China. No exact classification within Kra can be deduced for Hezhang Kra, but it was likely in contact with Kra languages spoken in the far northwestern areas of Guizhou, including various Red Gelao lects and perhaps also Lachi. Field documentation of Hezhang Buyi is now more urgent than ever, with fewer than 10, or perhaps even fewer than 5, elderly speakers remaining. Although we can never revitalize this language, Hezhang Buyi contains vital clues to the ethnolinguistic history of western Guizhou and surrounding regions, as it is one of the “relict languages” of Guizhou being rapidly absorbed by Southwestern Mandarin. It is my sincere hope that we can see more of this language documented before it forever sinks into the shadows of unrecoverable history.