HYOID -Henry Gray  Anatomy of the Human Body

I have been fascinated by language most of my life. That, I think, is why I like to write. I hardly knew any English when I came to the US.  I sat in my 5th-grade class in silence for three months and then, like a miracle, started to talk, just like all the other kids. But math is another story. Sixty-seven years later, I still need to revert to my primary language, German, to do my multiplication tables. Why is that?
I now speak without an accent.  I have been told that if one learns a new language before age 16, there is no accent; if one learns after that age, they remain with their accent all their life.  Why is that, and why can’t my wife, or JFK, say: “Ich bin ein Berliner” without struggling with the “CH” in “Ich”? It comes out like a mucous plug gurgling in the back of the tongue instead of a cat hissing.
As an adult, I experienced another quirk of language.  In my early doctor days, I realized that I needed to learn how to look into people’s stomachs to deal with illnesses in that organ.  The gastroscope was coming into common usage, but I could not learn how to use it unless I went to Japan to learn that skill for complex medical-political reasons, which will require another essay to explain. Suffice it to say, I went to Tokyo in 1974 to learn that skill.  I was fortunate to be taught by a famous Japanese professor for several weeks.  It took me the first week to understand him.  He kept talking about the “mucous rake” in the stomach. I finally figured it out.  He was talking about a puddle of mucous in the stomach – the “mucous lake.”  The adult Japanese cannot pronounce the “L,” and substitutes an “R” for it.  That issue popped up years later when I got evicted from first-class in an Asian airliner. I had bought a first-class seat for my wife, but I stayed in steerage. When it became dark, I snuck up to first-class and took the empty seat next to her.  In the morning, the stewardess discovered me and exclaimed, “You not first-crass, you must reave!” Embarrassed, I reft!
How did a tribe of tree monkeys learn to talk anyway? I have thought about this a lot and for a long time.  I concluded that what made us talk was that we started wandering the African savannahs when we came down from the trees several million years ago. We found it easier to walk on two extremities rather than four, which we needed up in the trees to keep from falling. 3.6 million years ago, in what is now Tanzania, a group of Australopithecus afarensis walked through wet volcanic ash that then petrified. It showed a modern gate with a heel strike first, and then the toes push off at the end of the step. The feet looked much like ours. With our bipedal gait, the head had to move directly over the shoulders. Otherwise, we would be looking at the ground all the time. Once we didn’t need our upper extremities to get around, we remembered the old biblical proverb, “Idle hands are the devil’s playground.” So, we looked for activities to do with them.  It took another million years for Homo habilis, which translates to handy man, to make the first recognizable tools. A tool to cut, an ax, was probably the first thing we made with our hands. Pointy things, that could be tied to a stick could be used to hunt rabbits or other small creatures. But then we realized that larger animals had more meat on them.  To hunt them required us to work in groups because a rhinoceros took a lot of cooperation to bring down, and was quite a dangerous undertaking. Making noises and gestures was a start, but not adequate for organizing several Neanderthals to surround and kill a Mammoth.  We needed language to do that.  “You come from behind, and I will come from the side and that guy from the other side, etc.” 
We had short necks when we lived in trees, but now that we had to talk, we needed better voice boxes and more articulate tongues and lips to make all those sounds that others could understand. The voice box moved lower in the neck, and probably in Homo heidelberensis, the structure of the most crucial bone for language evolved in the neck to attach the muscles that moved the tongue, the Hyoid bone.   Try to say an “L”  without using your tongue or a “P” without your lips – you can’t.  Making the vowel sounds requires more resonant spaces like the nose and sinuses, which we also developed.
With better communication, hunting became much more successful and gave us an upgrade in our diet to more proteins. Our brains got bigger from 640cc to our current size of 1350cc. And that is why we can no longer end sentences with a preposition, notwithstanding.