Deep Time Language History: Time Machine Needed

Humanity knows for sure that all Homo sapiens sapiens are genetically related. (In fact, we know for sure that all lifeforms on Earth discovered so far are genetically related.) We know this fact for sure because we can identify DNA sequences in all lifeforms that are mostly or completely the same and often that also accomplish similar biological tasks such as controlling the movement of molecules across cellular membranes.

Humanity has actually moved out of the African continent multiple times, but through genetics we know that all modern humans outside Africa are descended from the most recent outmigration about 70,000–60,000 years ago. (after 28:00) Humans that left Africa in earlier waves maybe more than 100,000 years ago all died out leaving no known descendants. (after 28:00) Scientists used to have a hypothesis that most humans outside Africa had died out because of a supervolcano explosion, but that hypothesis has been disproven and scientists are now back to square one with no solid theory about why no humans outside of Africa are descended from populations that migrated earlier than 70,000 years ago.

On one hand, while we can draw very exact genetic lineage trees going all the way to the origins of humanity’s evolution, it is impossible to do so for human languages.

Are all human languages actually even related to each other? Linguists would answer “probably,” but admit or even stress that proving this fact is impossible without a time machine. It is impossible to…