Why the Harappan script has not been deciphered:
- The inscriptions are extremely short — most seals carry only 4–5 symbols, unlike the long inscriptions or bilingual texts that helped decode other ancient scripts.
- No bilingual document (like a "dictionary" between Harappan and a known language) has ever been found, so there is no direct way to link the symbols to sounds or meanings.
- We do not know for certain which language family the underlying spoken language belonged to, which makes it far harder to guess what the symbols might represent.
- The script may be more pictographic/logographic (symbols standing for whole words or ideas) than alphabetic, which makes decoding mathematically much harder.
Efforts made to decipher it: researchers have used computer-based statistical analysis to study the patterns, sequence and repetition of symbols; compared the script with other ancient scripts of the region; and catalogued thousands of sign occurrences from seals, pottery and tablets to search for recurring patterns. Various scholars have proposed different (and often conflicting) theories — some suggesting a Dravidian-language link, others a Indo-Aryan or even a non-linguistic symbol-system — but none has been accepted as conclusively proven so far.