It is generally believed that Persian tribes migrated to the Iranian plateau in the late second millennium BCE, at a time when the region had long been under the sway of an Elamite population. Because of the location of Persian settlements in the Iranian plateau, contact between Iranians and the local Elamite people was inevitable. Persian and Elamite populations were in contact for up to 500 years before the emergence of the Achaemenid Persian Empire in the former eastern Elamite territories. The Elamite language was adopted and strongly reshaped by speakers of Old Iranian, who probably acquired Elamite as a second language for the purpose of writing and perhaps for communication with native Elamites. The latest documented phase of the Elamite language is known as (royal) Achaemenid Elamite. The nature of the impact of Old Iranian on it goes beyond the adoption of loanwords, and includes morphological restructuring. The main body of evidence for this evolution comes from a considerable collection of clay tablets written in Elamite that constitutes the Persepolis Fortification Archive dated the reign of Darius I. Based on these considerations, the present paper will discuss examples of language contact between Persians and Elamites. This paper analyzes the Old Persian and Elamite versions of multilingual royal inscriptions in the Achaemenid royal necropolis, Naqsh-e Rostam in order to further elucidate the nature of language contact between Old Iranian and Elamite.