[3] The language being yet unattested in readable contemporary sources, hypotheses regarding its nature are based on possible loanwords, the substratum in Vedic Sanskrit, and some terms recorded in Sumerian cuneiform (such as Meluhha), in conjunction with analyses of the Harappan script.
Its identification remains an open question, but most scholars associate it with the Indus Valley Civilisation.
[4] Asko Parpola identifies Proto-Dravidians with the Harappan Culture and the Meluhhan people mentioned in Sumerian records.
Jane R. McIntosh suggests one such possibility: Para-Munda was originally the main language of the civilization, especially in the Punjab region.
Witzel argued that the Rigveda showed signs of this hypothetical Harappan influence in the earliest historic level, and Dravidian only in later levels, suggesting that speakers of Austroasiatic were the original inhabitants of Punjab and that the Indo-Aryans encountered Dravidian speakers only in later times.