[elangoc]

Yes, some people propose that maybe the IVC writing isn't language at all. See this talk by one of the authors of a paper showing that it is, indeed, writing of a language: http://www.tedxsmu.org/events/tedxsmu-tuesday-7-5-11/ He used machine learning and the idea of entropy to prove his point, but as he says in the video, it's shocking how he got more menacing feedback -- to the level of death threats -- from saying that "the writing is a language" than saying "the language is Dravidian".

And as far as the Heras/Parpola Dravidian-based deciphering briefly mentioned in the talk, a much more expanded (and more compelling) deciphering is provided in the paper I linked above, called "The Indus Fish Swam in the Great Bath" by Iravatham Mahadevan. Ira. Mahadevan and Asko Parola are the the top 2 scholars of the IVC script. The paper also indicates several parallels to its other contemporary civilizations. That paper comes from the official website of the scholars involved in excavating and interpreting IVC sites.