They say we were just speaking and not writing anything for tens of thousands of years till a basic form of writing evolved just about ten thousand years back. Why this yawning gap ?
Here is my thought, humans actually wrote before they spoke. This procedure started back to the time when they first draw. These drawings later evolved into writing with specific symbols/letters.
I personally think that the major factor responsible for the emergence of speech is biological. Willy nilly, the biological mechanisms activating speech in human beings are a natural part of their speech development at a particular age. However, writing is a medium of transferring ideas through the application of some kind of alphabetic system. Consequently, writing developed after speech because it took men a very long time to invent and agree on an alphabetic system.
Some claim that we as tribes could communicate using wall sketches and paintings even before a basic speech system evolved. In that case these pictoglyphs could prove otherwise as a collectively agreed upon speech system could have wvolved later. But , assuming the same level of complexity for a speech system to translate into a written language, one might not be able to put the cart before the ox . It requires a systemaic evolution from thought to speech and then writing , leaving drawing out of the evolution line up.
The Native American culture, before the Europeans arrived, made extensive use of oral history, but they did not have the technology and resources to create permanent written records. Their culture did not need written records, other than "winter counts" preserved on animal skins, which were essentially memory aids.
I suspect the prehistoric Asian and European hunter-gathers and even the earliest farmers similarly relied on oral history. They made permanent stone carvings, but probably felt little need to preserve records that were easily transportable from place to place.