Sino-Tibetan languages
Linguist Edward Sapir suggested that the Sino-Tibetan languages are related to Na-Dené. A fringe hypothesis by Sergei Starostin suggested that Na-Dené (including Haida) may belong to the much broader Dené–Caucasian superfamily, which also contains the North Caucasian languages, Sino-Tibetan languages, and Yeniseian languages. This proposal is rejected by nearly all current linguists.