Concept: Alien’s don’t laugh. Not the way we do at least. Their version of laughing is like making a noise in their native language that literally means “I find this amusing’
So when they meet a human for the first time and the human finds it hilarious that the alien cant fit through the door, but the alien is even more confused because the translator doesn’t know what the human is saying. They are making noise, the alien can tell that much but the don’t know what they are saying.
and the human finally straighten back up, wiping at its eyes, “Sorry for laughing man but that was funny” the human makes the same noise as before just a little softer and a little less loud and the alien is so confused.
So they ask the human what they were doing and the humans like “laughing? wait… you guys don’t know what laughing is???”
and the aliens like nooooo….
so the human has to explain what laughing is “it’s when we find something funny. That’s how we let people know we think the thing is amusing”
“like this???” and the alien does a series of clicks and hisses that sound more scary than humorous but when the human looks at the translator in their hands it flashing the text “this is amusing. I am amused by you.”