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 itÂ 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.Â Again and again, you said the word of what you wanted or what you had to offer.