Eli5: When the first languages were being developed, how did everyone possibly learn and even agree on the set sounds for words?

Question

A long long time ago, humans went from grunts to some kind of primitive language then to an advance language.

How did a region possibly learn and agree that the sound “tree” for example meant that big thing over there?

Maybe my family would agree and say, but then our neighbours or tribe some 20km away?

Then for every word, tenses, grammar?!

I imagine it took a long time but I can’t even comprehend how you would transition from grunts to even a basic common language for a larger region like ancient China, Egypt, or aztecs.

They obviously did accomplish it, but how?

In: 44

Answer 1

The same way words like “gnarly” or “on fleek” are agreed to. A small group starts using the word, then all the “cool” kids are using the word to show membership in a group, then maybe it becomes more accepted and standard as more people use it.