The first simple languages spoken by Homo erectus likely developed around 500,000 years ago. This would have been a dramatic development of paramount importance.
Prior to spoken languages, members of a group communicated with one another by grunting or through simple noises and hand gestures. Spoken language allowed group members to exchange complex thoughts and ideas, and pass on their culture from one generation to the next.
Now groups could discuss plans, teach techniques, explain how to track animals, or where to go to find water, as well as form religion and folklore.
The knowledge of one generation could now be passed down to the next, building from generation to generation, expanding the human experience.