I don't think there is anything particularly useful in knowing about the origins of language in and of itself, but understanding the origins of language yields very useful and powerful information.  Language etymology simply tells us that the 5000 daughter languages all came from one parent language 50,000 years ago in Africa.  So it matches perfectly with the "archaeological" out-of-Africa theory, and the "genetic" out-of-Africa theory.  But that's not what I found interesting and powerful.  Clearly, this evidence says that it was language that underpinned the success of the early humans that spread throughout the world and took it over.  
 
One thin slice of this rich history, such as the evolution of the adverb since the 14th century, would be a life's work.  The study of modern English in the last hundred years alone would be fascinating.  It is mind boggling to trace all the languages back 50,000 years.  But since the 1800's, scientists have been doing just that, and the evidence is sufficient to convince the people who study it that this is a solid theory that they could bet their careers on - that's not to say it's not rife with errors and filled with holes.
 
I have been convinced that language brought with it more than one key advantage to early humans that launched them to worldwide success until now.  There are the obvious advantages to language, like the passing of skills and crude yet effective codification of measurements and mathematics.  I think there were many higher primates that were dabbling in crude communicative codification of things like measurements and mathematics.  Others passed along skills, or used words too for various reasons.  It is a matter of utmost importance to address the role of the rudimentary perceptions when discussing the success of early humans as it relates to language.  These early humans integrated the precept into codified language and that changed everything.  Bringing any of these primal precepts together through codified relationship systems would constitute a language, if the results of the joining could be expressed with words.   An early, unsuccessful humanoid would have a word for apple, and they would have a word for the number three.  The question is; could they join them together, and go on to express to another person that they wanted 3 apples?

 
It is established that the humans that could join precepts to concepts and express those concepts had a huge advantage over the other humanoids that could not.   This is where Jaynes left off in the "Origins of Consciousness".  In Origins he continually related the evolution of language with the evolution on consciousness and human success and development.  In the preface of the book he said that he intended to write another book explaining what his discovery could teach us, but didn't.  He would have started his follow-up book by making the obvious conclusion; language had it's origins in, is driven by and will continue to evolve in the grand context of "integrated thinking" - of joining precepts into concepts, and concepts into higher and higher levels of concepts.  And then, early humans had to convey those concepts throughout their early civilization of 2000 people, effectively enough to exact broad sociological change.  Language therefore, is not a vital function of communication; it's a vital function of thinking.  Communication is best seen as a necessary evil, but the concepts were the things that made all the difference in early man's actions.  It was actions that were taken in the real world around them, coordinated with language that made the critical difference for early humans.  Communication is the mailman, not the mail.  If Jaynes were honest enough in his second book, perhaps he would have written how there is one grand cause for the varying degrees of consciousness in the earth's population.  There are different levels of consciousness and human success and happiness because there are different degrees of efficacy in integrated thinking.  Then, he would have to be really honest to understand and write that there must be something affecting the method used by the unsuccessful humans that has been properly adapted by the successful ones.  In their very thinking, successful humans had a methodical way to piece together, and then convey integrated concepts.  For this to happen, the concepts would have to be represented by a common sign or sound in order to be understood by others.  In the first successful human civilization something could be said to everyone in the society and everyone knew what it meant.  Early humans were not just saying primitive, instructions or things related to basic math or measurements, these humans were relating integrated concepts at a certain level. For something to have meaning it must have had a meaningful context. This means that a contextual harmony with the world around them was necessary for an integrated concept to be successful in reality.  This is done when the person or society puts a concept into action by taking actions, which are based on the concept.  To be successful in reality, the early humans had to be successful with reality, and relating it through the known factors through context did this.  To put it quite simply, adding context to the two or more precepts and facts on which a concept is based does this.    There had to be solid intuativity in the early languages for them to be understood by all.  But it is one thing to have a language that is robust enough to convey instructions for physical movements, basic math and measurements, it is quite another to convey integrated concepts such as objective morality or justice.  Language, teamed with integrated thinking would be like a nuclear reactor being turned on inside the minds of the early humans.   Thinking was augmented with language, and language grew as concepts grew in number and complexity.  Clearly, 50,000 years ago, once the method was codified by which concepts could be turned into free flowing language, there would have been a real, earth shattering change in their society.  But it is this method that must be established first and that is where Jaynes would have had to face the ultimate reality that bears down on human success.  There is one factor that can influence the success of the concept/language nuclear reactor; and that is how well the process propels the society towards 1) World Domination    2) Successful and happy societies and individuals who thrive over the long term.  In other words, the "reality-to-integration ratio" had to be sufficient for early humans to translate their new, bright ideas into the actions that would bring them real success.  The first society did one thing right that the other talkers did not; they matched their concepts against that which was real and used language as a reliable way to codify the transmission of those concepts.  

This would all be perfect if the method of matching concepts to sounds in this way was the end of the story, but something other than reality can also be spread verbally or symbolically as well.  There could be language for things that were, in varying degrees representative of reality - from fibs to outright deception.  These concepts, let lose on an individual or society, would harm that individual or society because it would hinder their ability to form concepts that were useful and successful.  The reason for this is that very complex concepts require accurate information that is in harmony with reality.  If there is information contained in or being considered in the formation of a concept that is wrong, the mistake will eventually cost the thinker some value, and perhaps his success.  It is worth noting that the more mistakes made means the more harm done.  The early societies that did the least harm to themselves, as a whole, would triumph over the societies that harmed themselves with unreal thinking.  The more 'realistic' humans dominated the non-realistic ones to the point that the early humans are no longer on the earth.  It is reasonable to protract this trend into the future until one of two things happens; 1) human society becomes complex, thus dangerous enough where unreal thinking causes human extinction.   Humans that totally succeed in adhering their conceptual integration method to reality dominate the earth.

 
In his first book, Jaynes said that written and spoken language changed dramatically when consciousness was invented, but at the same time there were byproducts like war, premeditated killing and a whole variety of immorality, fraud, force, coercion, social ills and upheaval.  Just prior to the invention of consciousness, there was a whole host of changes taking place in the world, both good and bad ones.  In today's competition for world domination in the future one must realize that the formula hasn't changed, and neither has the cause of failure, but now there is a hyper-change introduced into the mix of variables; consciousness.  Early humans and their language did not have to contend with the 'me metaphor' model that was used as the new way of seeing the world.  Reality-twisting and reality avoidance became rampant during the years where consciousness was invented by humanity.  Like the early advantages, this new thinking model was used to out compete the other, unconscious humanoids off the planet.  (I say humanoid because there were many human-like organisms that were very similar to us but failed or were absorbed because of the lack of consciousness).  So there are two milestones in the development of humans; the first was the advent of conceptual thinking and its ensuing codification in language, and the second, the leap of human development called consciousness.  There were new values and benefits for humanity, plus it brought destructive byproducts like envy, deception, force, fraud and coercion.
 
The lesson is that nothing has changed since the very beginning except it's become harder to navigate and calculate what to do in a complex world.  The complexity of the world is of our own doing, a spawn of our own magnificence and achievement.  As our conceptual ability expanded, our ability to communicate those concepts struggled to keep up.  We could always think faster than we could write.  But eventually we had to deal with a complex and deceptive world, one that is mired in a mind-created reality.  Reality was, and is being avoided by individuals and whole societies, and being ignored or rationalized as irrelevant - but reality is never irrelevant because it will always assert itself in the end.  That is why it is called reality.  If it cannot assert itself, then it is just  a factor that can be manipulated and not a reality, for reality always asserts itself.
 
Early humans struggled with reality because they lacked knowledge to formulate solutions.  Ironically, it was the advancement of knowledge and expanded consciousness that caused a new problem.  Later came consciousness with its good and bad sides to cause the modern-era humans (last 3500 years) to struggle to find reality through a cloud of force, fraud, deception and lies.  Nevertheless, the need to adhere to reality in order to succeed has not changed.  Totally integrated reality, or forming concepts that are honest with the facts in context, is the only means to achieve a harmonious methodology for living.  The human mind, now armed with a powerful thinking model called consciousness continues to grasp at understanding reality, then integrating it into their actions.  The very same process used by the first group of successful humans goes on to this day and remains the human organism's survival mechanism.  The degree to which our thinking is in harmony with reality, is the degree to which we will be successful.

There is no doubt that the first humans to succeed demonstrated a unique ability to adapt methodology to their thinking to produce integrated concepts.  It is just as evident that consciousness introduced a means and method of it's own that could both enhance and hinder the effects of consciousness.  This introduction of consciousness was invented around 3500 years ago.  The choice now for today's humans is clear; we must seek out and eliminate any non-reality that hinders our ability to integrate into wider and wider concepts.  We must eliminate mysticism because it further hinders, or blocks our ability to tie together more and more complex concepts that are required to adapt to ever increasing complexity in the world around us.  The world becomes more complex as our society puts highly integrated concepts into action.  The concepts that allow deception are becoming more complex, just as the concepts that increase human happiness, health, love and prosperity.  [For example, the mystical ideas used by parasites like preachers, politicians (on the left, right and center), the academe, dishonest media types, (surprisingly) many business 'leaders' and most lawyers but not all.  Highly developed concepts allow individuals to gather unearned power, psuedo self esteem, adulation and unearned livelihoods.  They do this by manipulating, fortifying and then preying on the unreal concepts held by individuals and society at large.  On the other hand, there are those who create values for others, and then give the benefits of those values to anyone who agrees, voluntarily to integrate the concept's advantage into their actions.  This is the atomic unit of all business, and indeed all value creation that takes place in business, love and friendship relationships.  In this case, of business, money is the language used to translate concept into actions.  The monetary systems of the world basically do the same thing; they allow values created in the integrated mind to be translated into traceable, tangible values.  These values are exchanged in a benevolent and voluntary way.  There are always competing ideas in any area of life, but make no mistake, over time the winner will always be the one that honestly integrates with reality.  The concepts that help the human individual and every society on earth to achieve happiness and success in prosperity and survival are the concepts freest of mystical bounds.  The generation that embraces the new method of thinking that deliberately eliminates concepts that are patently unreal or mystical will be remembered forever into the future as the greatest generation.  Once we are free of mystical bonds that shackle our minds, our concepts will expand limitlessly into wider “out-of-the-box” concepts.  Greater and greater success will be achieved, more and more values created while fewer and fewer would be destroyed.  This would lead to a new and better renaissance for humanity and our biggest lurch forward.  Mystical concepts could lead to the death of all life on this planet, and integrated concepts could lift humanity to higher and higher levels of integration with reality leading to boundless success, happiness, love and health.