[samatman]

> the oldest languages on the planet, as spoken by the oldest people

Begging your pardon, this is a nonsensical thing to say. One people are not older than another, and nor are their languages.

As it happens, the Khoisan show greater genetic divergence from the rest of the human race, indicating that as a population they have been relatively more isolated, for longer. This does not in any sense imply that they are in some way basal, such that it would be intelligible to call them older than other branches of the family tree.

This same objection applies to characterizing their languages in that way, we have no way of knowing if their languages are less or more prone to mutation than any other. We have rather less to work with, in fact, as the absence of literacy in their societies until modern times leaves us with no evidence at all. But it would be astonishing if their languages had no drift to them, and even "less drift" is a major and unsupportable claim, and these are the only ways in which it would be intelligible to say that those languages are older than another.