Hurrian language
The names of the Mitanni aristocracy frequently are of Indo-Aryan origin, and their deities also show Indo-Aryan roots (Mitra, Varuna, Indra, Nasatya). These Indo Aryan deities are listed in two treaties between Mitanni and Hatti from Hattusa: (treaty KBo I 3) and (treaty KBo I 1 and its duplicates), the kings involved are Sattiwaza of Mitanni and Suppiluliuma the Hittite. The British Museum considers these documents as being from a date around 1350 BC. The common people's language, the Hurrian language, is neither Indo-European nor Semitic. Hurrian is related to Urartian, the language of Urartu, both belonging to the Hurro-Urartian language family. It had been held that nothing more can be deduced from current evidence. A Hurrian passage in the Amarna letters – usually composed in Akkadian, the "lingua franca" of the day – indicates that the royal family of Mitanni was by then speaking Hurrian as well.