Time travel fic...
I like sci fi, and this includes time travel stories. People who find themselves in different cultures are fun. However, when someone travels a thousand years into the future and are able to speak to people with perfect clarity without the help of technology, it's kinda hard to suspend my disbelief. Go back just a few hundred years and it would be very difficult to communicate with anyone unless you'd spent a lot of time studying language from that time. So basically, I find it hard to believe that language thousands of years in the future would not have evolved at all. This also applies to stories where people travel to alien worlds.

It's fair enough if it is a story set in the past or future but without time travel. If we couldn't write these in modern language it would be difficult to write them in any enjoyable way at all.

So basically, if two people speak the same language when logic says they should not, provide an explanation. Technology, magic, I don't care. Please.