Some interesting observations and insights with regard to communications. Each of your have provided points to ponder. Each point helps to explain a portion of verbal communciations. I make the distinction of verbal communciations because most human communciation is non verbal.
Our human species - homo sapians - first developed verbal communciations about 100,000 years ago but the species had been in existance for hundreds of thoudands of years earlier. So, we must have had a pretty good form of communciations prior. to that. Humans had formed tribes, chosen leaders, hunded in groups, drew cave painings, and the species grew so they had familes - all of this without language skills.
Two other species, Homo erectus and Neanderthal had immigtated out of Africa at least 50,000 years before Homo sapians, But neither of those species developed language skills nor did they have the develpment of the cerebral brain as did Homo sapians. Both species were encounted by Homo Sapians when they immigtated. Homo sapians were the last to immigrate but while still in Africa they developed cerebral brain functions and with it the invention of language.They could communciate thoughts, ideas, even concepts. This advanced brain function probably provided superior life skills, (e.g., hunting tools, fishing skills, the bow and arrow and other weapons, devices and items). Eventually Homo sapains dominated the other species which eventually disappreared.
After thousands of years humans gave up hunting and gathering and created villages, towns and cites even empires but written language, in archological time, only came into existance within the last 10,000 years.
So, while communications is as old as humanity, language and the written form are still relatively current while nonverbal communications (body language) is as old as humanity. Current research has shown that we still use the brain functions of our earliest ancestors and the nonverbal body language skills are as powerful if not more so than when we were cave dwellers trying to survive a very hostile world.