> ...and it's clearly linked to our cognition.

People with global aphasia can still do arithmetic, follow causal reasoning, play chess, pass theory-of-mind tasks, etc. During non-linguistic reasoning, math, music and executive tasks, neuroimaging has revealed that the language centers in the brain are pretty darn quiet.

So the link, and the causal direction if any, is not really known.

There’s a great book called Paleopoetics by Christopher Collin’s that looks at exactly that

My entirely layman and unsupported conspiracy theory about language is that early hominids likely developed complex sign language and some primitive forms of writing now long lost to time, but vocal language only came with the necessary biology.