There is a phenomenon in anime called the fan sub. This is taking shows and movies that aren’t available in English, or aren’t available subtitled, and creating a subtitle version. My partner and I routinely watch a show that, for legal reasons, is called Case Closed in the United States and Detective Conan in Japan. (Well, Meitantei Konan, but you know what I mean.) The show has a character who is always telling riddles to the child characters (and the teenager-in-a-child’s-body characters, because okay) that involve an intricate knowledge of the language and writing systems of Japan. In the fan subs, the jokes have footnotes to explain them. Not, of course, that this makes them funny, but that’s the point. At least now they’re comprehensible.
Jokes are cultural. Comedy can translate, but any joke that relies on wordplay won’t. Anything that relies on a specific knowledge of the culture can fall flat, and that even if the language remains the same. There’s a joke in Twelfth Night that we don’t understand, because Shakespeare uses the term “cross-gartered,” and no one can agree on what that actually means. It doesn’t exist anywhere else. Productions of the play are left to figure out for themselves how to portray this ludicrous affectation without being sure if it’s what the audience at the time would have understood.
Obviously, this is a problem with any work, but jokes are particularly susceptible. Look at how poorly parodies that rely on intricate knowledge of a specific time age. Think how people would look at you if you made a joke about the Budweiser frogs—and yet people made them, and even put them in major network TV shows. And that’s not just in English, that’s within the lifetime of most of the readers and contributors here. The “Long Long Man” series of commercials from Japan has made its way to international fame via YouTube, and with luck will continue to be something we remember (because it is amazing), but most commercials vanish again into pop culture obscurity.
Even the basics don’t necessarily translate—sex and bodily functions are universal, of course, but how we talk about them and what we say is not. The oldest recorded joke is something about how women pass gas in their husbands’ laps, and is that a thing? The Babylonians thought it was. How a culture sees these things is enormously specific, and in particular the slang used for such things changes rapidly and is often necessary background for any jokes. Oh, a lot of jokes about that we can get now, but it’s possible we’ve missed them in other works because the context is gone.
If you’re reading this and aren’t a native English speaker, I’m not telling you anything you don’t know. Heck, if you’re reading this and not from the US, you probably know this, too. Or are from the US and consume a lot of pop culture from other countries. I’m reminded of how Sergio Leone couldn’t be persuaded that “duck, you sucker” isn’t an extremely common American phrase despite the assorted Americans involved in making the movie he called that promising him they’d never said it in their lives. Translation issues matter in ways people don’t necessarily think about until they don’t get the joke.