Indo-Aryan superstrate in Mitanni

Some loanwords in the variant of the Hurrian language spoken in Mitanni during the 2nd millennium BCE are identifiable as originating in an Indo-Aryan language; these are considered to constitute an Indo-Aryan superstrate in Mitanni (or in Mitanni Hurrian). The words are theonyms, proper names and technical terminology related to horses (hippological).

It is generally believed that Indo-Aryan peoples settled in Upper Mesopotamia and northern Syria, and established the kingdom of Mitanni following a period of political vacuum, while also adopting Hurrian. This is considered a part of the Indo-Aryan migrations.

Linguistic context
Professor Eva von Dassow concurs with the presence of Indo-Aryan terms in Mitanni vocabulary, but cautiously advises against the notion of an "Indo-Aryan takeover". Michael Witzel argues for the antiquity of the Indo-Aryan words attested in the Mitanni data, since they almost certainly predate linguistic developments attested in the Rigveda.

In a treaty between the Hittites and Mitanni (between Suppiluliuma I and Shattiwaza, c. 1380 BC), the deities Mitra, Varuna, Indra, and Nasatya (Ashvins) are invoked. Kikkuli's horse training text (circa 1400 BC) includes technical terms such as aika (Vedic Sanskrit eka, one), tera (tri, three), panza (pañca, five), satta (sapta, seven), na (nava, nine), vartana (vartana, round). The numeral aika "one" is of particular importance because it places the superstrate in the vicinity of Indo-Aryan proper (Vedic Sanskrit eka, with regular contraction of /ai/ to [eː]) as opposed to Indo-Iranian or early Iranian (which has *aiva; compare Vedic eva "only") in general.

Another text has babru(-nnu) (babhru, brown), parita(-nnu) (palita, grey), and pinkara(-nnu) (pingala, red) for horse colours. Their chief festival was the celebration of the solstice (vishuva) which was common in most cultures in the ancient world.

The Mitanni warriors were called marya (Hurrian: maria-nnu), the term for '(young) warrior' in Sanskrit as well, formed by adding the Hurrian suffix -nnu; note 'mišta-nnu' (= miẓḍha,~ Sanskrit mīḍha) "payment (for catching a fugitive)".

Sanskritic interpretations of Mitanni names render Artashumara (artaššumara) as Arta-smara "who thinks of Arta/Ṛta", Biridashva (biridašṷa, biriiašṷa) as Prītāśva "whose horse is dear", Priyamazda (priiamazda) as Priyamedha "whose wisdom is dear", Citrarata as Citraratha "whose chariot is shining", Indaruda/Endaruta as Indrota "helped by Indra", Shativaza (šattiṷaza) as Sātivāja "winning the race prize", Šubandu as Subandhu "having good relatives" (a name in Palestine), Tushratta (tṷišeratta, tušratta, etc.) as *tṷaišaratha, Vedic Tveṣaratha "whose chariot is vehement".

Attested words and comparisons
All of the following examples are from Witzel (2001). For the pronunciation of the sounds transcribed from cuneiform as š and z, see Proto-Semitic language.

Names of deities
From treaties of Mitanni.

Horse training
From Kikkuli.