In the Doctor Who episode "Utopia", the main characters travel trillions of years into the future and find humans and "kind" (human-like people) speaking English. How do they know English? Languages evolve: the English of even a thousand years ago is unintelligible today, and trillions of years is almost unimaginably longer.
- I've only ever watched two Doctor Who episodes ("Smith and Jones" and "Utopia", both from the new series), so this question may very well be answered clearly in another episode. (E.g., maybe there's some kind of force field around the Doctor and other major characters that serves the same purpose a Babelfish does in the Hitchhiker series.) If so, then please post that as an answer!
- The same question could be asked about other people in the two episodes I've seen (listed just above), such as the plasmivore, the slabs, and indeed the Doctor himself. But in all those cases, it's possible that they (even off-camera) learned English from anglophone humans (as indeed the rhinoceros-like police chief did). The same can't readily be said about the future humans and kind.