The Indus script, also known as the Harappan script, is a corpus of symbols produced by the Indus Valley Civilisation. Most inscriptions containing these symbols are extremely short, making it difficult to judge whether or not they constituted a writing system used to record the as-yet unidentified language(s) of the Indus Valley Civilisation. Despite many attempts, the 'script' has not yet been deciphered, but efforts are ongoing. There is no known bilingual inscription to help decipher the script, and the script shows no significant changes over time. However, some of the syntax (if that is what it may be termed) varies depending upon location.
The first publication of a seal with Harappan symbols dates to 1875, in a drawing by Alexander Cunningham. By 1992, an estimated 4,000 inscribed objects had been discovered, some as far afield as Mesopotamia, due to ancient Indus–Mesopotamia relations, with over 400 distinct signs represented across known inscriptions.
Some scholars, such as G. R. Hunter, S. R. Rao, John Newberry, and Krishna Rao have argued that the Brahmi script has some connection with the Indus system. Raymond Allchin has somewhat cautiously supported the possibility of the Brahmi script being influenced by the Indus script. Another possibility for the continuity of the Indus tradition is in the megalithic culture graffiti symbols of southern and central India (and Sri Lanka), which probably do not constitute a linguistic script but may have some overlap with the Indus symbol inventory. Linguists such as Iravatham Mahadevan, Kamil Zvelebil, and Asko Parpola have argued that the script had a relation to a Dravidian language.
Periodisation of the Indus Valley civilisation
By 1977 at least 2,906 inscribed objects with legible inscriptions had been discovered, and by 1992 a total of () 4,000 inscribed objects had been found. Indus script symbols have primarily been found on stamp seals, pottery, bronze and copper plates, tools, and weapons. The majority of the textual corpus consists of seals, impressions of such seals, and graffiti markings inscribed on pottery.