The Nostratic hypothesis links many of the worlds language families and claims that they all descended from a single proto-language. This is a controversial theory. Currently, there is not enough information to show that the languages are truly sharing a familial origin and not simple the result of borrowing. Nostratic is one among a group of proposed “macro-families” in historical linguistics. Some others are: Macro-Jê, Macro-Waikurúan, Macro-Mayan, Macro-Siouan, Penutian, Na-Dene, Austric, Dené–Caucasian, Eurasiatic.