Earlier quoted context omitted.
Static how? Obviously there is no ancient audio. Is ancient Tamil writing readable by modern Tamil readers?
Written scripts have used to change all over time. It is not possible to read at the get go, but after some practice, yes, any one can read old Tamil. Given that about ~55% [1] of written inscription are from Tamil, it is one of the proficient. How do you measure the language change [2]? There are several approaches, the one I remember reading about is, you fetch the most basic kernel of a language, like very simple…
The "after some practice" makes this a bit of a squishy claim. For example, Malayalam and Tamil split less than 1000 years ago and are both descendants of Old Tamil. I would be surprised if "after some practice" a Malayalam speaker couldn't also read Old Tamil, or for that matter Modern Tamil (and vice versa for a Modern Tamil speaker learning Malayalam).
So is Tamil somehow older than Malayalam? I think not.