The human race came to fruition when they developed the capability to manipulate words as tools. This probably happened between 35,000 and 70,000 years ago.
One of the first things we did with our new tools was to ask questions. It didn't matter that some of the questions had no answers or were constructed so that any answer would be meaningless or just wrong. We invented answers anyway.
Refusing to admit that our answers were inventions, we claimed they came from divine authorities, the gods. Those who had invented different answers made the same claim. We killed each other to justify the divine origins of our answer sets. We called that religion.
One important question was where we go when we die. Somebody decided that our breath, inspiration or spirit carried on much as we had in life, an idea that proved so popular it was borrowed by many religions. Religions might differ in opinion as to whether that spirit went to a happy place, a place of suffering or just wandered invisibly about this world, thereby justifying more strife.
Use of the new tool gave us an advantage for survival. Educating the young in survival techniques was easier and more thorough. Dangers could be described without having to be seen. Experience could be carried over several generations. New techniques could spread rapidly over vast territories.
Those who learned to speak soon learned to decorate their bodies with jewelry, a new invention that spread quickly over trade routes that sprung up. Carvings appeared and, deep in unlighted caves, art was created on the walls. If the art was used in initiations, itself a form of magical invocation, and magic for curing, hunting and harvest, the true magic is that it developed into pictographs that became writing.
Writing solidified words, not just by giving them permanence in media like clay tablets. Because the written word lasts a long time, we can see how our spoken words have drifted in sound and meaning from the way they were a few decades or centuries before. We can also note from contexts that the meanings of particular words shifts, often reversing completely. Spoken language is as fluid as the air it floats on and as impermanent as its speakers while written language will outlast its creators.
By its relative permanence, written language has become a standard for the spoken language. Writing has brought formality to the once casual process of communicating.