There are certain sorts of jokes which have only to do with the substitution of the unexpected word in a familiar context. If you translated something into French and then had it translated back into English by somebody who didn’t know the original, you’d lose what was funny.
More Tom Stoppard quotes :
In January 1962, when I was the author of one and a half unperformed plays, I attended a student production of 'The Birthday Party' at the Victoria Rooms in Bristol. Just before it began, I realised that Harold Pinter was sitting in front of me.Tom Stoppard