I'm not sure if this is exactly what the commenter above was referring to (or what you're looking for), but a really tricky aspect of translation is humor. Thi

I'm not sure if this is exactly what the commenter above was referring to (or what you're looking for), but a really tricky aspect of translation is humor. Things like alliteration, rhyming, and homophones are all incredibly difficult to move across languages and those are _easy_ compared to the slang and idioms. An example: In Tagalog, the word for blue is "asul" which more or less directly leads to an English/Tagalog joke about how "People have been telling me to cheer up all week, they keep calling me an 'asul'". Which to understand, you need to be fluent in Taglog, English slang and have the cultural background to understand that "blue" means sad (which isn't universal).