On the Origins of Language
Linguists know that languages change drastically over the course of a few thousand years, so drastically that there’s no telling what the original human language was like or how it came into being. Language consists of words, not rocks, so there are no linguistic fossils comparable to the fossils in rock that reveal ancient stages of plant and animal evolution. We won’t find echoes of the first words embedded in the walls of a cave.
As a result, scientific speculation about the origins of language has remained speculation. In the 19th century the Linguistic Society of Paris went so far as to prohibit discussions on the origins of language, as a waste of time. In the 21st century we know much more about language, evolution, and neurobiology, but that merely offers more input for speculation.