Yep. The Mississippi River could one day back up and start going the other way---but it sure would make news!
What I'd like to know is how and why people spoke such complex languages as Sanskrit back then, and they don't now. How is it that civilization advances and language degrades? I'd rather know that, than where Sanskrit arose.
They probably didn't speak it. The grammar and alphabet were formally systematized and regularized; the vocabulary was based on contemporary spoken languages that varied from village to village. Latin is a great language: monstrous and living vocabulary even now, compact, but irregular. They copped their alphabet from the Greek alphabet and a lot of the vocabulary, and the leftover Greek letters were used for numbers--I M V D, etc.