The writing on the stone tablet is revealed to be Elamite, which is an extinct language once spoken by the Elam, an ancient civilization that occupied the far west and southwest portion of modern Iran and a small portion of southern Iraq. The Elamite civilization first showed up in the Copper Age around 3000 BCE and historical records indicate the civilization and their language died out around 539 BCE.
The Bactrian Kingdom, also known as the Greco-Bactrian Kingdom, was a Greek state during the Hellenistic-era of classical antiquity. It was founded in 256 BCE and covered most of present day Afghanistan, Uzbekistan, Tajikistan and Turkmenistan and after 180 BCE parts of Iran and Pakistan. The kingdom fell around 120 BCE due to repeated attacks and invasions by a nomadic group of people from Asia known as the Yuezhi, who were originally from ancient China.