My theory of human evolution posits that many features of human nature began because they increased specialization and trade. One is language. Language began with single words, I assume. The use of single words began and grew because they helped the two sides of trade find each other. The first language, in other words, was the first advertising. Advertising has two sides: (a) saying what you have too much of and (b) saying what you have too little of.
Single words are still used this way. Stores are often adorned with single words that say what they sell. When you go to an unfamiliar store, you may use single words to find what you want (“thermometers?”). The use of single words to convey desires is clear in a paper by Alexander Graham Bell, which I learned about from Electric Universe by David Bodanis. Bell (the inventor of the telephone) was a teacher of the deaf and wrote a paper about teaching deaf children language. His method involved labeling objects around the house with their names. One of his students was a five-year-old boy:
One morning he came downstairs in high spirits, very anxious to play with his doll. He frantically beat his shoulder with his hands, but I could not understand what he meant. I produced a toy-horse; but that was not what he wanted. A table; still he was disappointed. . . . At last, in desperation, he went to the card-rack, and, after a moment’s consideration, pulled out the word “doll” and presented it to me.
For a different view of why language evolved, see this paper by Hauser, Chomsky and Fitch.
“The use of single words began and grew because they helped the two sides of trade find each other.”
But surely the necessity for sounds that provided warning of threat from predators (and other danger) preceded words for trade? And perhaps vocalizations that encouraged silence in the presence of predators. Before we could trade we had to be able to survive…
And the need to communicate specificity of edible plant locations might have encouraged enough fine-grained cognition so that words developed — think of the bee waggling behavior that locates pollen.
I’m not saying your theory is wrong, but parts of it are perhaps over-stated.
I see words as a representation. As what they represent gets more complex, so do the patterns used to create them. I think the most pure form of communication is sharing an experience. However even that experience is limited by a person’s perception. I often lose perspective on what communication really is, its an abstract, not the reality of the moment. It intrigues me as to how much is perceived without words. This would reason to place great emphasis on health and awareness to maximize perception and cognition. To better understand and communicate with one another to get what we want and also redefine what we want.
The most persuasive arguments I’ve encountered on the origins of language trace it to mother/child interactions. Babies’ wants are very simple, and not different from those of other species, so cannot sustain language development. Teaching is an activity can take advantage of every conceivable improvement in language technology.