The inscriptions in the north-western regions of India – are in Kharoshti script. This region was ruled, in the 2nd century BC, by Indo-Greek kings. On the coins of that time, the names of the kings were inscribed in Greek and Kharoshti script. It helped in reading the Kharoshti script.
1. European scholars who knew Greek Kharoshti scripts could compare the letters in the inscriptions, and they could easily read them.
For example, the sign “A” was used to write names like Appolodotus in both the scripts.
2. James Prinsep recognized that the language in the inscriptions was Prakrit. This made it possible to read the longer inscriptions.