The father of one of my Chinese tutors used to work at a coal mine (in an administrative position) but after his wife went away to care for her sick mother he wanted a job without night shifts to better care for his two children. He decided to make a business of fixing bicycle tire pumps. People who fixed bicycles were common but hardly anyone fixed the pumps.
Was it hard to start such a business? No. There was a tradition in his small town of persons walking through neighborhoods announcing what they had to sell. Like ice cream trucks. Coal, fruit, baked goods, and other things were/are sold that way. (He preferred to buy his coal directly from the mine.) At first, he used his unaided voice, later he got an electric megaphone, now he has a recording.
I believe human language began like this. Language began and grew because it facilitated trade. Facilitating trade facilitated occupational specialization, the essential difference between humans and other animals. Words — single words, repeated many times — were the first advertising, the original Craig’s List. Again and again, you said the word of what you wanted or what you had to offer.
Arguably it’s language itself that has been subject to intense natural selection, while humans as a species have been selected mainly to become better hosts for it. Those poor slobs, humans, now live or die by the language “skills” they host. They live in unpleasantly crowded places, eat mass-produced food, squint at screens and push buttons all day, and do whatever people they’ve never even met want.