Vasco-Caucasian languages
Vasco-Caucasian is a hypothetical language family or phylum whose extant members are Basque, Northwest Caucasian (Abkhaz-Adyghe), Northeast Caucasian (Nakh-Daghestani) and Burushaski, although not Kartvelian (South Caucasian). Although first proposed by John Bengtson, it had a precedent in the "Asianitic" group proposed by the Polish geographer Bogdan Zaborski c. 1970.
Extinct languages such as Hurro-Urartian, Hattic, Etruscan and Iberian have also been proposed to belong to Vasco-Caucasian, which is an extension of Sergei Starostin's North Caucasian family (which groups together NEC and NWC) and in turn is part of a larger Dene-Caucasian group also including Sino-Tibetan and Yeniseian.
Octavià Alexandre is an adherent of this hypothesis, but Jörg Rhiemeier considers it unwarranted. That is, he doesn't mean that it is wrong; but if these languages are related to each other, the time depth probably exceeds the range of the current comparative method.