I think your source can be summarized by: “These issues and many others are undergoing lively investigation among linguists, psychologists, and biologists.”
https://www.linguisticsociety.org/resou … uage-begin
Hardly just “not knowing all the details”, in actuality, there is no naturalistic explanation for the origin of languages.
“The evolution of the faculty of language largely remains an enigma.”
We argue instead that the richness of ideas is accompanied by a poverty of evidence, with essentially no explanation of how and why our linguistic computations and representations evolved. We show that, to date, (1) studies of nonhuman animals provide virtually no relevant parallels to human linguistic communication, and none to the underlying biological capacity; (2) the fossil and archaeological evidence does not inform our understanding of the computations and representations of our earliest ancestors, leaving details of origins and selective pressure unresolved; (3) our understanding of the genetics of language is so impoverished that there is little hope of connecting genes to linguistic processes any time soon; (4) all modeling attempts have made unfounded assumptions, and have provided no empirical tests, thus leaving any insights into language’s origins unverifiable. Based on the current state of evidence, we submit that the most fundamental questions about the origins and evolution of our linguistic capacity remain as mysterious as ever, with considerable uncertainty about the discovery of either relevant or conclusive evidence that can adjudicate among the many open hypotheses.
One of the sad things about the ‘God did it’ approach is that it ignores and even dismisses great fields of study like evolution and linguistics. The theistic ‘god did it’ answer is fundamentally a ‘know nothing approach,’ a plea for ignorance.
No fields of study are being dismissed. As a matter of fact, we need more research. If people want to study evolution and linguistics, then go for it. But, if no naturalistic explanation is found, a supernatural explanation cannot be ruled out.