Can I just add that I learned about Scots accents the hard way when me and a couple of mates went to see MacBeth at the Edinburgh Festival back in the sixties.
The late Matt McGinn palyed the gatekeeper - we couldn't understand a word.
Didn't matter too much though, the three witches were played by stunning-looking young women in diaphanous see-through costumes - played hell with my late adolescence!
Jim Carroll