For questions about the writing system of the Indus Valley culture approx. 2000 BCE and its underlying language(s).
The Indus Script also known as Harappan script is an undeciphered script from the Indus Valley. Known inscriptions are usually very short (5 characters) and the longest known inscription has a length of 27 characters. The script typically occurs on clay seals.
Little is known about this script, and it is even disputed that it is a representation of spoken language.