A “mysterious” language change? I’m dubious. 3500 B.C. is the approximate date of the invention of writing, specifically cuneiform. The Sumerian language certainly had to be in existence for a long period of time before a written form of it could have been developed.
All existing languages evolved from prior languages, so of course there is a substratum to Sumerian that could be described as “non-Sumerian.” People have lived in the region of the Euphrates since the dawn of mankind. We’re not talking about “virgin territory” for new groups of people to move in and exploit, so the most likely explanation is that the language(s) of the indigenous people simply evolved over the many millennia that their ancestors lived there. Farming was invented in the same area 6,500 years before Sumerian was set down in cuneiform. It isn’t hard to see how ancient agricultural terms might be preserved in the Sumerian language, even as the rest of the original language changed, fell into disuse, and was replaced.
This goes back to the hyperbole discussion in the Walton/Longman thread on the flood. It was routine for ancient historians to inflate figures. Even hundreds of years later (if not a thousand), Josephus would say 1 million Jews were killed in the Roman War, while Tacitus put the number of dead at 600,000. The true figure? Probably around 500,000, but who knows for sure?
The thing to remember is that the ancients wrote history much differently than we do. They were not interested in the bare, undiluted facts. For them, history had a purpose and a direction, so their histories highlighted the lessons to be learned. In Mesopotamia, the lesson was that “kingship descended from the gods,” and the gods created humanity as a labor force to serve their needs. The purpose of their myths was to support the theology of empire. Israel provided a counterpoint to that interpretation of history …
Here is a link to a good article on the Spell of Nudimmud. In a nutshell, the story is not about the shift from one language to many, like the tower of Babel story in Genesis. Rather, the spell of Nudimmud “means that mankind shall speak in one tongue, which is Sumerian, and that the Lord of Aratta has to submit to this. … Sumerian is to be spoken everywhere. Trade can and will be instituted through acceptance of Sumerian as an international language, and cuneiform as the technical carrier for this language. Needless to say, this puts Sumerian on a higher level than every other language, which notion is tersely reinforced by the statement that this is the language in which Enlil is to be praised.”
The author summarizes his conclusion thus: “The will to turn Sumer’s superiority into supremacy is the driving power of the story. This superiority is shown by pointing out Sumer’s superior ethics (cleverness instead of war; technologies for the good of all mankind), its superior knowledge (the technologies involved in solving the unsolvable; writing), its superior organization (setting up techniques and ways of international intercourse; writing again) – in short, its superiority per se (Sumerian).”
So, just as Gen. 1:26-28 reverses the Mesopotamian concept of the king as imago Dei and applies that concept to all men and women, Gen. 11 and the tower of Babel incident once again serve as counterpoint to the Mesopotamian culture of empire and exploitation.