Explained: Why is it so difficult to decipher the Harappan writing system?

– Devising appropriate procedures to isolate or segment the stream of symbols into a sequence of single signs;

–Reducing the set of signs to the minimal set for the writing system forming (its alphabet, syllabery, or inventory of signs) by identifying all allographs (the same sign written in a variant form, for example a printed ‘a’ and a cursive ‘a’);

–Assigning to each symbol their specified value, whether phonetic or otherwise;

–Trying to match these values to a specific language.

In the case of the Indus script, scholars have struggled to solve many of these subproblems. This is due to three main factors.

No multilingual inscriptions: What is perhaps most helpful to decipher unknown scripts is direct comparison with known ones, made possible by multilingual inscriptions which have the same content in two or more scripts. There is evidence that the Indus Valley Civilisation had robust trade links with the contemporaneous Mesopotamian Civilisation whose cuneiform script was deciphered in the early 19th century — but no multilingual inscriptions have been discovered so far.

The most famous multilingual inscription is the Rosetta Stone, which contains a decree passed during the reign of Ptolemy V in 196 BCE in three scripts: Greek, demotic (a later ancient Egyptian script), and hieroglyphics. The inscription was instrumental for the decipherment of Ancient Egyptian hieroglyphics in the 1820s by French philologist Jean-François Champollion.

The Pashupati seal of Mohenjodaro

Language not known: Undeciphered scripts/languages fall in three basic categories, according to Andrew Robinson, the author of the influential Lost Languages: The Enigma of the World’s Undeciphered Scripts (2008). These are: “an unknown script writing a known language; a known script writing an unknown language; and an unknown script writing an unknown language.”

A seal bearing the very common unicorn motif.

Of these, the third category is the most challenging to decipher as they provide scholars with the least number of points of reference to go by. The Indus script falls in this category. Although scholars have variously postulated the script representing different languages, there is no clinching evidence to seal the debate. Without knowing what language the script represented, scholars have struggled to allocate phonetic sounds to the script’s symbols.

Mould of a seal showing a man fighting two tigers

Not much known about civilisation: The greater the availability of material evidence — in the form of inscribed artefacts — the higher the likelihood of a script being deciphered. This is because each different artefact, and the context in which it was found, can provide some insight into the script it is inscribed with. Although some 3,500 seals have been identified till date, given that each seal has on average only five characters inscribed, scholars simply do not have enough material to analyse.

Add to this the fact that very little is actually known about the Indus Valley Civilisation, compared to contemporaneous ancient civilisations in Mesopotamia and Egypt. Many Harappan sites remain undiscovered, and those which have been uncovered remain underexplored.

Mould of a seal showing an elephant in movement.

This general paucity of information has made it difficult to decipher its script. A lot more archaeological work will have to be carried out to provide philologists, epigraphists, and linguists greater opportunity to understand the writing system.