In the rocky hills of Central Asia, a number of walls bear a mysterious script that’s scrawled in an unknown written language. Thanks to the recent work of a team from the University of Cologne, parts of this ancient script are starting to be revealed, shedding light onto the pre-eminent culture that wrote it. 

The so-called “unknown Kushan script” is a writing system that’s been found across parts of Central Asia. The script has been seen across numerous sites in modern-day Tajikistan, Afghanistan, and Uzbekistan, but has never been successfully deciphered.

It was used between about 200 BCE and 700 CE by the early nomadic peoples of the Eurasian steppe, such as the YuèzhÄ«, and the ruling dynasty of the Kushans. 

One of the most prominent legacies of the powerful Kushan empire was spreading Buddhism across Central Asia and China. They left behind amazing artworks and a collection of impressive fortresses, as well as this unusual writing system. 

In a new project, linguists have made a major breakthrough in understanding the language by studying a bilingual inscription found in Tajikistan – written in Bactrian and unknown Kushan script – and a trilingual inscription from Afghanistan – written in Gandhari or Middle Indo-Aryan, Bactrian, and unknown Kushan script.

The researchers were able to decode the message using a similar method employed on the Rosetta Stone. Written in 196 BCE, this ancient rock features a decree written in three languages: Ancient Egyptian hieroglyphs, Demotic script, and Greek script. Since scholars could still understand Ancient Greek, the Rosetta Stone became a valuable key to deciphering Egyptian hieroglyphs.

The breakthrough in understanding the unknown Kushan script came when the researchers noticed the royal name Vema Takhtu, which appeared in both Bactrian parallel texts, and the title “King of Kings,” could be identified in the corresponding sections in the unknown Kushan script. Using the parallel texts, the linguists were able to note certain character sequences and even work out the phonetic qualities of some individual characters, including 15 different consonantal signs and four vocalic diacritics.

As for the precise meaning of the messages, that still remains unknown, but the researchers say their work has helped to illuminate the murky linguistic history of this part of Central Asia.

The team argues that the Kushan script recorded a completely unknown Middle Iranian language, which they’ve dubbed “Eteo-Tocharian”. They believe it most likely served as an intermediary language within the development of  Bactrian to Khotanese Saka, an ancient language of western China.

It also seems that at some point in time, the newly deciphered language was one of the official languages of the Kushan Empire alongside Bactrian, Gandhari/Middle Indo-Aryan, and Sanskrit. 

“Our decipherment of this script can help enhance our understanding of the language and cultural history of Central Asia and the Kushan Empire, similar to the deciphering of the Egyptian hieroglyphs or Mayan glyphs for our understanding of ancient Egypt or Mayan civilization,” Svenja Bonmann, first author from the department of Linguistics at the University of Cologne, said in a statement.

The study is published in Transactions of the Philological Society.