To English speakers, the word, “peanut” isn’t especially funny. But “peanut” in Serbian, “kikiriki” is widely considered by Serbs to be the funniest word in their language. This raises the question of why people laugh at some words (“poop”) but not at others (“treadmill”). Does it come down to their meanings? Or are people responding to their sounds? Psycholinguist Chris Westbury set out to discover the answer.