system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: The evolution of language, from cavemen to Shakespeare.
gpt
The truth is we know almost nothing about any language more than about 10,000 years ago. That's about the farthest back linguists have been able to reliably reconstruct.

Among the theories about the origin of language is a hypothesis that all languages derive from a single ancestral language, spoken in Africa about 100,000 years ago. This language, according to some (and this is *highly* conjectural), might have sounded like a modern San language. These languages are informally known as 'click' languages, and they have relatively large sound inventories. They sound very different from English.

Language changes over time, and as populations move apart, the languages they speak grow more and more different, until the people who speak them can no longer understand each other. That's the basic story of variation.

There are other theories about language change that try to fill in the gaps, but these are all (you guessed it) highly conjectural and often controversial. Among these theories is one about the tendency of languages to shift from analytic to agglutinative to fusional to analytic and so on. This means that a language might begin as the sort of language that, like Chinese, conveys ideas entirely with separate words. Instead of marking things like tense or plurality with suffixes, each of these concepts is conveyed with its own word. Over time, common combinations of these words gets fused together into the sort of language that looks lime Latin. Then, over more time, those endings get dropped, and the language begins to resemble English, then ultimately Chinese once again.

The particular story of English involves this process, as English dropped a lot of the suffixes that typified the Germanic languages. The development of English is a long and intricate story that involves contact with other languages, especially Norse and French.

But that's another story for another day.