You know what words are funny and which words are not funny,\" says the comedian, played by Walter Matthau. From this \"correlation plot,\" the researchers identified six different clusters or categories of funny words: insult, sex, party, animal, bodily function and expletive. Since many of the words on the human-rated funny list fell into more than one category, the researchers needed a more precise measurement of how a word's meaning translated into comedy. Westbury and his team looked at the form of funny words, things like word length or the individual sounds (phonemes) that make up each word. That helps explain why there are so many \"k\" and \"oo,\" sounds in the funny word lists.