Let’s assume I’m in England. How far back would I be able to understand and be understood by other English speakers? At what point would the language become too different to understand?
Not to forestall further answers, as more can always be said but the great /u/bloodswan wrote an excellent answer to a similar question I asked a few months back: When I hear Chaucer spoken in Middle English, it almost sounds more like Dutch than English. But though Shakespeare is closer in time to Chaucer than the present, his English is much easier to understand. What happened to English in between, and why?