If we take some major patterns from todays world an for a moment "eliminate" what we know about its history, and instead pretend we have to figure it out, we would often get a very different story and explanation of origin.
Imagine we only know the present languages and cultures but nothing about their history. If we then wanted to reconstruct that history by reason or linguistic sciences or some cultural theories I think the result wouold almost inevitably be very far from the actual history.
Perhaps we would not see english or spanish, portuguese or russian as originally european languages and arabic as originating in the arabian peninsula? but if we found that out we would most likely not be able to make a very good theory about how those languages spread, since that history is not that straightforward.
I didn't find the right solution from the Internet.