In this video from The Open University, we learn about the Globe Theater's experiments with "Original Pronunciation" (OP), which is exactly what it sounds like–English as it was pronounced at the time Shakespeare's plays were written and first performed. Unsurprisingly, OP is quite different from modern pronunciation, and often changes lines dramatically. Often lines rhyme in the OP accent, but do not in a modern accent (also known as Received Pronunciation, or RP). My favorite is an example late in the video, when "proved" is pronounced like "loved," as they are supposed to rhyme in Sonnet 116. Brilliant and illuminating.

Let David and Ben Crystal guide you in this ten-minute video:

If Ben Crystal's voice sounds familiar, it may be because he does narration work in addition to his stage and screen work. Dude could read the phone book, I'd tune in.

There's more on this in a course from The Open University. Also highly relevant: When Did Americans Lose Their British Accents?

(Via Kottke.)