Talking like Dead People

Historical linguists and language evolution researchers have been working on how languages sounded like a long time ago. One method, pioneered by William Labov in the 1960s, is to just listen to old people talking, since people tend to keep pronounciations learnt in childhood.

Of course, that only works for languages several decades ago. If you want to know how a language sounded like centuries ago, a surprising source of information is songs where you know what word has to rhyme with what. Of course, just because you know a bunch of words sound the same doesn't mean you know what they sounded like. That requires additional information, such as pronunciations from slow-changing dialects (e.g. of more isolated communities).

David Crystal has been teaching actors at the Globe how to pronounce Shakespearean English. The BBC has a good report on this:

They say their accents are somewhere between Australian, Cornish, Irish and Scottish, with a dash of Yorkshire - yet bizarrely, completely intelligible if you happen to come from North Carolina.

Somehow, North Carolina doesn't sound like an isolated linguistic community. That must be a coincidence.