Or are there any examples of historic languages with far fewer words and being much more basic?
Interestingly enough, there are not! Nor are there any examples of "more basic" modern languages (*).
In fact, there's a sort of axiom in modern linguistics that all languages with native speakers are equally expressive. Anything that can be expressed in English can also be expressed in Arapaho or Cantonese or Swahili—or Ancient Greek or Ancient Egyptian or Classical Nahuatl, for that matter. You might have to invent new words for concepts like "computers", since the Ancient Egyptians didn't have those, but you can work around that with, say, "a machine that does calculations".
Now, there are some languages that are more basic: "pidgins", which arise naturally when speakers of different languages need to make basic communication work between them. These tend to have extremely simple grammar without much expressiveness. But, even more interestingly, when children grow up speaking these languages, things change—the result is a creole, with full-fledged morphosyntax and as much expressiveness as any other natural language!
This is one of the big pieces of evidence in favor of a "language mechanism" in the human brain. Different theories then go in different directions from there, arguing about how much exactly is innate. But it seems clear that some underpinning of language is, in fact, intrinsic to humans.
So, where did language come from in the first place? Good question—nobody really knows! There are quite a lot of different hypotheses, but very little evidence to test them against. So for now, it remains one of the big unsolved mysteries of linguistics.
(*) There's a very controversial claim that the Pirahã language spoken in South America is actually simpler and more basic than any other. Some linguists support it; others disagree with it. Personally, I think such an extraordinary claim requires extraordinary evidence, and there simply isn't enough evidence to back this one up.
P.S. If you want to investigate this further, John McWhorter's research on creoles would be a good place to start. Some other sources are mentioned in the comments.