A few corrections in you article Ramkey ...
Firstly Tamil or any Indo Aryan - Dravidian languages are not the oldest languages in the world.
We must understand that the evolution of languages happens thru a concept called Proto Languages.
Proto Languages provide the infrastructure for modern languages using
1. Read and Learned methods.
2. Written Script.
3. Grammatical rules.
Proto-languages are, by definition, are hypothetical languages reconstructed by linguists on the basis of above 5 point, and hence no proto-language has any historical record of existnace. So is the case with Proto-Dravidian languages.
Proto-North Dravidian, Proto-Central Dravidian and Proto-South Dravidian languaes are estimated to be around 500 BC using the earliest mentions in more than 3 of the above 5 points. But due to a dearth of comparative linguistic research into the Dravidian languages, not many details as to the grammar, epoch, or location of Proto-Dravidian are known. Simply becoz the lack of the proofs supporting the existance of them using above 5 points.
But Vedic Sanskrit scores all 5 and was found to be existed in all the above means since around 1500 BC!
Also I am skeptical about claims that tamil existed before Sanskrit. Although Tamil words were found in the Vedas they were originally vedic sanskrit and not other way round.
So does that mean
Vedic Sanskrit predates Tamil? Most likely.
Vedic Sanskrit prediats Modern Sanskrit? Ofcourse.
Tamil predates Modern Sanskrit? Least likely although .
Oldest books which cover all the Dravidian languages which can point to Proto-Dravidian forms is Dravidian Etymological Dictionary still consist only of lists of related words without further explanation; therefore for a talented linguist Proto-Dravidian offers large possibilities.
Further researches in Proto-Dravidian may surprise with sufficient proofs that they may be oldest forms in Indian subcontinent.
Sadly only little is known and only researchers can do is speculate about proto dravidian hiostory.
Till then Vedic Sanskrit and thus arguably Sanskrit are assumed to be older than Dravidian languages.
Further proof to this claim can be made using this article about the script and grammer based evolution of languages where Saskrit stands before Tamil (although interestingly Tamil is the only indian languages placed neck to neck with Sanskrit indicating about its ancient-ness)...