The true evolution of human language is inevitably intertwined with the history and evolution of the species itself. Look at the languages clustered around
Europe -- a handful of them evolved directly from
Latin. Still others, while they might have come from older common
roots than
Latin and its ilk, are inevitably similar on some level because the whole lot of them evovled from
Proto Indo European, the granddaddy of all languages west of the
Ural mountains -- and then some. I can't speak as such for the
eastern languages, but I know that for all their cultural diffrences,
Chinese and
Japanese are related. The indigenous languages of
Africa are related. The indigenous languages of the
new world are related, and so on.
Perhaps, though, the Forbidden Experiment was asking the wrong questions. A better start might have been, "how many original languages did mankind have?"
Language, in my humble, non-expert opinion, began with the need for humans to use their evolutionary "edge" - their brains - to their advantage. To do this, they needed to communicate quickly and effectively, to compete in pre-historic times. Brainpower was their survival tactic. If the hunter-gatherers could get to the food sources first, they could feed their tribe. They could increase their population. Necessity is the mother of invention. Language began, because we needed it to survive. Words for things like food, walk, run, eat, drink, sleep, see, yell, hurt, cry, fuck, and so on were the first. They were the most fundamental. They were probably, way back in the past, adapted from grunts and hoots we used to make when we were apes. The first languages probably consisted of a relatively low amount of words, which were not highly defined and probably all sounded somewhat similar, composed of gutteral and phoentic sounds. Ever wonder why all those "basic" words tend to be just one syllable? Ever wonder why profanity tends to be just one syllable?
And so, when we settled down and became agriculturalists, we suddenly had a mess of new, important concepts on our hands. Not only that, but were sedintary. We could have possessions, write down our wisdom, and pass it on to future generations. All of a sudden, one generation could build on the knowledge of the last. We therefore had a ton of new intellectual concepts. We had no words for things like that, but we soon developed them. The more abstract concepts in language were newer. We were smarter, as a culture, so we could handle bigger words. Multisyllabic words became more commonplace. They evolved, though, from those small, basic words that were our first. Like building a house, the foundation comes first.
One could almost say that humans who were more adept at learning and mastering language were, evolutionarily, more fit to survive. Those who had a working command of language would hear the news and know where the food, water, and shelter were. The ones who didn't understand were left out of the loop. They became sickly and died, for lack of adequate resources that they would have otherwise gained by knowing a language. Thus, those who had the gene for a powerful language processing lobe in the brain survived to reproduce. Today, where language has long since become an absolute necessity, we all have such sections in our brains, just as we have nimble fingers.
The reason the forbidden experiment wouldn't work is because we only develop, linguistically, what we need in order to function. Back when we were all hunter gathered, we didn't need too many words. We have more things to deal with in this day and age, so we have more complex words to express and describe it. The development and complexification of language come slowly, just as did our civilization.
And that, my friends, is why good ol' Psammetikos wouldn't have found the original language of mankind, even if his experiment had succeeded. Language development is completely situational. Any language the kids he isolated would have come up with would be influenced by sounds they heard, by the color of the walls where they were kept, by the methods in which they obtained their food and their clothes, and so on. Just like today's languages developed, slowly, as their presence became necessary.