Akkadian

iš - for, to (CAD I 222, AHw. 391)

Early Mari.

PS
*ˀiš - to, for (Arakelova 2001:29)
The reconstruction is not entirely certain. Akk. iš is only attested in a specific group of texts (the archaic liver models from Mari); moreover, it is sometimes considered to be an equivalent of the terminative marker -iš. Throughout EthS this preposition can only be distinguished as a part of other prepositions, for which one may also suppose other ways of division. See Arakelova 2001:29–30.