existential clause which is different from ordinary possession verbs like "to have" Such similarities do not constitute sufficient evidence of genetic relationship all on their own, as other explanations are possible. Juha Janhunen has argued that although Ural–Altaic is to be rejected as a genealogical relationship, it remains a viable concept as a well-defined language area, which in his view has formed through the historical interaction and convergence of four core language families (Uralic, Turkic, Mongolic and Tungusic), and their influence on the more marginal Korean and Japonic. Contrasting views on the typological situation have been presented by other researchers. Michael Fortescue has connected Uralic instead as a part of an Uralo-Siberian typological area (comprising Uralic, Yukaghir, Chukotko-Kamchatkan and Eskimo–Aleut), contrasting with a more narrowly defined Altaic typological area; while Anderson has outlined a specifically Siberian language area, including within Uralic only the Ob-Ugric and Samoyedic groups; within Altaic most of the Tungusic family as well as Siberian Turkic and Buryat (Mongolic); as well as Yukaghir, Chukotko-Kamchatkan, Eskimo–Aleut, Nivkh, and Yeniseian. Relationship between Uralic and Altaic The Altaic language family was generally accepted by linguists from the late 19th century up to the 1960s, but since then has been in dispute. For simplicity's sake, the following discussion assumes the validity of the Altaic language family. Two senses should be distinguished in which Uralic and Altaic might be related. Do Uralic and Altaic have a demonstrable genetic relationship? If they do have a demonstrable genetic relationship, do they form a valid linguistic taxon? For example, Germanic and Iranian have a genetic relationship via Proto-Indo-European, but they do not form a valid taxon within the Indo-European language family, whereas in contrast Iranian and Indo-Aryan do via Indo-Iranian, a daughter language of Proto-Indo-European that subsequently calved into Indo-Aryan and Iranian. In other words, showing a genetic relationship does not suffice to establish a language family, such as the proposed Ural–Altaic family; it is also necessary to consider whether other languages from outside the proposed family might not be at least as closely related to the languages in that family as the latter are to each other. This distinction is often overlooked but is fundamental to the genetic classification of languages. Some linguists indeed maintain that Uralic and Altaic are related through a larger family, such as Eurasiatic or Nostratic, within which Uralic and Altaic are no more closely related to each other than