The root may be transliterated as "Jié"- or "Tsze2"- and an older form, < "kiat", may also be reconstructed. This ethnonym might be cognate with the ethnonyms of Yeniseian-speaking peoples, such as the Ket and the Kott (who spoke the extinct Kott language). Pulleyblank (1962) connected the ethnonym to Proto-Yeniseian *qeˀt/s "stone". Vovin et al. (2016) also pointed to *keˀt "person, human being" as another possible source. Furthermore, Vovin has demonstrated that the single known phrase in the Jie language is a better fit to Yeniseian languages than Turkic languages. Alexander Vovin also suggests that the Xiongnu spoke a Yeniseian language, further connecting them with the Jie people. Western Washington University historical linguist Edward Vajda spent a year in Siberia studying the Ket people and their language and his findings helped substantiate such conjecture into the origins of the Ket people, where DNA claims show genetic affinities with people of China and Myanmar, suggesting a Sino-Tibetan origin. He further proposes a relationship of the Ket language to the Na-Dene languages indigenous to Canada and western United States, and even suggests the tonal system of the Ket language is closer to that of Vietnamese than any of the native Siberian languages. Among the Yeniseian languages, Jie is hypothesized to be Pumpokolic. Vovin, Vajda, and de la Vaissière have suggested that Jie shares the same idiosyncrasies with the Pumpokol language, and the two are therefore closely related. This argument is strengthened by the fact that in northern Mongolia, Yeniseian-derived hydronyms have been demonstrated to be exclusively Pumpokolic, while influence from other Yeniseian languages is only found further north. This therefore lends credence to the theory that the Jie are a Pumpokolic-speaking tribe, and confirms that the Pumpokolic-speaking Yeniseians existed in the core territory of the Xiongnu state. Other sources link the Jie to the Lesser Yuezhi ("Xiao Yuezhi" 小月氏), who remained in China as vassals of the Xiongnu and then the Han dynasty. Only one phrase in the native language of the Jie is known. The source for this phrase was a Kuchean Buddhist monk and missionary Fotudeng.