Proposal of an overarching northern Eurasian language family, still of uncertain validity.
Holger Pedersen was the first to suggest that the Indo-European , Uralic , Altaic , Afroasiatic , and other language families might belong in one broad category (Nostratic). In the 1960s Vladislav Illich-Svitych made a detailed case in favour of the hypothesis and added Kartvelian (see Caucasian languages) and Dravidian to the list; he began reconstructing Proto-Nostratic but died in 1966 before finishing. Important contributions to this theory were also made by the Russian-born Israeli linguist Aron Dolgopolsky. The hypothesis remains highly controversial.