A very hypothetical macrofamily of languages. It links the following very, very disparate groups:

Most linguists consider the evidence for Dene-Caucasian to be extremely tenuous and unconvincing. The isolates such as Basque have been separated from whatever relatives they once had for so long that it is now virtually impossible to reconstruct any relationship with others equally distant in time and space.

The groups of related words claimed to have been found usually only bear a tenuous phonetic and semantic link, no more than you would expect to get by chance. The supposed sound shifts needed to account for them are vague, unlikely with more solidly reconstructed families.

It might seem strange to connect Chinese, very poor in morphology, with the highly inflected Basque, but actually Chinese might not be representative of Proto-Sino-Tibetan, since Tibetan has a richly inflected verb-final auxiliary reminiscent of that of Basque.