The Harappan language (also Indus language) is the unknown language of the Bronze Age (3rd millennium BC) Harappan civilization (Indus Valley Civilization).

The language being unattested in any contemporary source, hypotheses regarding its nature are reduced to purported loanwords and substratum influence, notably the substratum in Vedic Sanskrit and a few terms recorded in Sumerian cuneiform (such as Meluhha), in conjunction with analyses of the undeciphered Indus script.

There are a number of hypotheses as to the nature of this unknown language:

• The Elamo-Dravidian hypothesis places it in the vicinity of either Elamite or Dravidian, perhaps identical with Proto-Dravidian itself. This is endorsed by Kamil Zvelebil, Asko Parpola and Iravatham Mahadevan. However, all attempts to decipher the Indus valley language as dravidian have failed.

• Michael Witzel (2001) as an alternative to the Elamo-Dravidian hypothesis suggests an underlying, prefixing language that is similar to Austroasiatic, notably Khasi; he calls it "para-Munda" (i.e. a language related to the Munda subgroup or other Austroasiatic languages, but not strictly descended from the last common predecessor of the contemporary Munda family).

• a "lost phylum", i.e. a language with no living continuants (or perhaps a last living reflex in the moribund Nihali language). In this case, the only trace left by the IVC language would be historical substratum influence, in particular the substratum in Vedic Sanskrit.

• an Indo-European language, close or identical to Proto-Indo-Iranian: suggested by Shikaripura Ranganatha Rao but mostly dismissed in scholarly mainstream.

• a Semitic language: Malati Shendge (1997) identified the Harappan culture with an "Asura" empire, and these Asura further with the Assyrians.

There is a handful of possible loanwords reflecting the IVC language. Sumerian Meluhha may be derived from a native term for the IVC, also reflected in Sanskrit mleccha, and Witzel (2000) further suggests that Sumerian ^GIŠšimmar (a type of tree) may be cognate to Rigvedic śimbala and śalmali (also names of trees).

The question has some political significance in Indian communalism, the Dravidian and Indo-European hypotheses being embraced by Dravidian and Hindu nationalists, respectively (see Indigenous Aryans for details).

See also

• Substratum in Vedic Sanskrit

• Indus script

• Elamo-Dravidian

• Proto-Dravidian

• Dravidian homeland