There is the tooling hypothesis, i.e. that the ability to build tools also brought the need to communicate how to build the tools.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5774752/
https://www.wired.com/2013/09/tools-and-language/
The structure of steps in a process necessitated structured grammar and thought. US philosopher Daniel Dennett is a proponent of language-as-debugging. Our rational faculty was an emergent property of evaluating statements. Errors provoke laughter as a debugging response.
https://en.wikipedia.org/wiki/Theories_of_humor#Detection_of...
Notable comedian George Carlin demonstrated a real genius for debugging language. His piece about the progression from "shell-shock" to PTSD is a good example.