Relationships
Some or all of the four Uralo-Siberian families have been included in more extensive groupings of languages (see links below). Fortescue's hypothesis does not oppose or exclude these various proposals. In particular, he considers that a remote relationship between Uralo-Siberian and Altaic (or some part of Altaic) is likely. However, Fortescue holds that Uralo-Siberian lies within the bounds of the provable, whereas Nostratic may be too remote a grouping to ever be convincingly demonstrated.
The University of Leiden linguist Frederik Kortlandt (2006:1) asserts that Indo-Uralic (a proposed language family consisting of Uralic and Indo-European) is itself a branch of Uralo-Siberian and that, furthermore, the Nivkh language also belongs to Uralo-Siberian. This would make Uralo-Siberian the proto-language of a much vaster language family. Kortlandt (2006:3) considers that Uralo-Siberian and Altaic (defined by him as consisting of Turkic, Mongolian, Tungusic, Korean, and Japanese) may be coordinate branches of the Eurasiatic language family proposed by Joseph Greenberg.
Read more about this topic: Uralo-Siberian Languages