In French, "knock, knock!" is translated as toc, toc! However, "Knock, knock!" jokes - like the one below - do not exist:

Knock, knock!
Who's there?
Lettuce.
Lettuce who?
Lettuce in!

(i.e. Let us in!)

In fact, toc toc is used to describe someone as crazy.

Nevertheless, there are jokes in French such as:

What do you call a cabbage underwater?
A chou-marine.

(i.e. chou means "cabbage", while sous-marin is the French word for "submarine".)

How do you translate jokes in another language in a way that maintains its humour?

I've been reading a book by Howard Buten, translated in French by Jean-Pierre Carasso, which I picked up from a hostel in Barcelona. It's called Quand j'avais cinq ans je m'ai tué ("When I Was Five I Killed Myself") and it's about an 8-year-old autistic boy called Gilbert who is sent to a Children's Trust Resident Centre for hurting his classmate Jessica.

Cultural references to Popeye, Zorro and Thanksgiving weren't too strange in another language, however lines from nursery rhymes such as "Kookaburra sits in the old gum tree" or "Star Light, Star Bright, the first star I see tonight" were interesting to read aloud to see whether you could get the same rhythm in French.

And then... there was a "Knock, knock!" joke. In the book, Jessica doesn't understand the joke that Gilbert tries to tell her - but it doesn't make sense in French anyway:

"-- Toc, toc! j'ai dit. (C'était une blague.)
-- Qui est là?
-- Bouhou!
-- Bouhou qui?
-- Oh y a pas de quoi pleurer, je lui ai dit."

("Knock, knock!" I said. It was a joke.
"Who's there?"
"Boo hoo!"
"Boo hoo who?"
"Oh, there's no reason to cry," I told her.)

In French, qui ("who") doesn't fit to make the joke funny. As a translator, is it better to stay true to the original text despite its potential incomprehensibility in another language? Would it be better to tell the joke in English? Or should a similar joke be told, but an original French joke, which captures the same sentiments?

A similar dilemma occurs in the English translation of the French play and movie Le Dîner de Cons (literally translated as "The Idiots' Dinner" but with the English title "The Dinner Game"). One of the characters' surname is Sasseur, which sounds like sa soeur ("his sister"). The confusion leads to a hilarious scene in the movie , but if you relied on the subtitles, would it make any sense?

...anyway, that's enough Viennese coffee house pondering for today.