Native origin, the mainstream theory, according to which the Basque language would have developed over the millennia entirely between the north of the Iberian Peninsula and the current south of France, without the possibility of finding any kind of relationship between the Basque language and other modern languages in other regions. Basque-Iberism theorizes the existence of a kinship between the Basque and the Iberian language, and therefore between their speakers. Caucasian origin theorizes that the Basque language and the languages of the Caucasus may have a direct relation, explaining why they share some linguistic typologies absent in the Indo-European languages.