I just read an article in which linguistic scientists are trying to work out a time-traveler's phrase book. That sounds incredibly cool! Hardly anyone thinks about time travel and not being able to communicate. Sure, they probably have different accent or something, but you could still understand them, right? Well, this article says, sure, some words would work out. But that's like maybe five or six.
Time travel is a fun topic to plumb, because we'll probably never come close to knowing. I hope in writing that I'm jinxing the whole thing and someone travels back in time tomorrow. So, what's in store for him? Let's pretend he goes to the 6th century A.D. in North America. Except, it's not called that.
It's called New China. But the natives speak perfect French. Our astounded traveler is baffled. Not only was he hoping to parlez in English, but he's been thrown this impossible curve. How could this have happened? How could inhabitants who immigrated across a land bridge from Asia be speaking courtly French, who haven't even established their language yet from across the pond?
Well, I'll tell you why: because it's time travel. Since it is an impossible (at this time) development of which we know nothing, then anything could happen, really. Who's to say that our guy is the first one who went back. It could have been H.G. Wells. Or Amelia Earhart. Or Antoine de Saint-Exupery. He spoke French. And who knows when and where he went back. Or for what purpose.
Also, what about the universe this time traveler visits? Is it ours? Or as Back to the Future hypothesizes, one of many infinite alternate 1985's? Perhaps he goes back and it's too crazy to explain away. Like Hunter S. Thompson at your mom's New Year's party. So what is the goal there? Living with the tribal Native Americans who speak French and hunt abominable snowmen during the invisible ice age with internal-combustion engine-powered hovercraft and binoculars could be fun.
If I was this traveler, my goals would be thus: try to survive and not die (priority), befriend everyone and become the cool guy at the party, find my way back to my original reality, and if all else fails, then try to leave my archeological mark in such a way as to make no mistake what happened to me, or failing that, scare the shit out of future generations.