Voice of the cheshire cat in Alice in Wonderland?

In Lewis Carroll's book, the Cheshire Cat famously says, "we're all mad here". In the Disney animation this is modified to "most everyone's mad here".

When Alice meets the Cheshire cat, she's very confused about which way to go. The cat tells her that one path leads to the Hatter's house, and that the other path leads to the March Hare's house, and that both these characters are mad (crazy)!

In THAT direction,' the Cat said, waving its right paw round, lives a Hatter: and in THAT direction,' waving the other paw, lives a March Hare. Visit either you like: they're both mad.'

But I don't want to go among mad people,' Alice remarked.

Oh, you can't help that,' said the Cat: we're all mad here. I'm mad. You're mad.'

How do you know I'm mad?' said Alice.

You must be,' said the Cat, or you wouldn't have come here.'