Wellerisms have been perpetrated from Ancient Sumerian times at least (the Ancient Sumerians were the ones who invented writing, so Wellerisms could have been about for millennia before that. But luckily we have no record of them).
So what's a Wellerism?
It's a sort of joke.
"We'll have to rehearse that," said the undertaker as the coffin fell out of the car.
Re-hearse: geddit? Yes, it's awful. But even the philisopher Plato was unable entirely to resist the opportunity to cause pain in this way:
'The water will tell you,' said the guide, when the travellers asked him how deep the river was.
Presumably the gag works better in Greek.
Wellerisms can be found all over the place: they've been recorded in Holland, the Baltic, in Slav languages, as well as the African languages Yoruba and Chumburung.
"Ruff," said the dog, as it sat on the cactus.
There. I think I've inflicted enough pain for one day, so I'll stop, there. It's interesting, though, isn't it?
"Simply remarkable," said the teacher when asked his opinion about the new whiteboard.
Nuts and Bolts: Wellerisms. Wellerisms are named after Sam Weller, a character in Charles Dickens' Pickwick Papers (1836-7) who was always saying things like: 'Out with it, as the father said to the child when he swallowed a farden [farthing]'.