a term defined is different from a thing existing.

is it though?! "language is the house of being"

A term by any other name would still smell as sweet as ... ;)

That might in fact be true.

If we define humans as having a sufficiently sophisticated language, and using a term to reference one's entire species is characteristic of that, then at a stretch we could define the first human being as the child of proto-humans who first invented this linguistic concept.

Point taken :)

What if "human" would be replaced by "ape"?

Sure. There are several similar arguments made in this thread. Such as, before the word "run" was first used, we could only walk quickly.

The logic of these arguments is fine. I just noticed a way to nit-pick your implementation of it.

> If we define humans as having a sufficiently sophisticated language

That would be hard to object to.

> and using a term to reference one's entire species is characteristic of that

But this is easy to object to. People can easily do without a term for the species; it's more common to use tribal names, so that a contrast is drawn between different groups of humans (as opposed to between humans and animals, or humans and gods).

Terms for humans as a species come along pretty quickly, but they're not universal.