Funny, not funny... what's the difference?

Some words are funnier than others. I’m betraying no secrets of the International Humorists Guild to tell you this. If you want to get a laugh with a joke or a piece of prose, or even with a poem, word choice is critical.

“Turkey” is funny. “Chicken” is not.

“Salami” is funny. “Ham” is not.

“Agony” is funny. “Pain” is not.

Why should this be so? It’s not simply the number of syllables, or the familiarity of the object or sensation being referenced. Granted, salami is arguably less common than ham, but “zipper” is funny, while “button” isn’t. There’s nothing particularly more familiar about zippers vs. buttons. On the other hand, “hematoma” is funny, while “bruise” is not. There is no clear association.

Is it the way the sounds of the funny word can be stretched out in delivery for comic effect? Is it the prevalence of hard vs. soft vowel sounds?

“Numb” is funny. “Dead” is not.

“Purple” is funny. “Blue” is not.

“Constipation” is funny. “Diarrhea” is not.

Even things which aren’t particularly funny can be classified as such, in one category or the other. Does this mean that words are not inherently funny, but only become so because I predispose the reader to agree with me? Are readers looking for a laugh, and willing to accept my categorization, not because it’s correct, but because it doesn’t actually matter?

“Soup” is funny. “Hamburger” is not.

“Sleepy” is funny. “Tired” is not.

“Stabbing” is funny. “Burning” is not.

Perhaps there’s an onomatopoeic component which underlies the humor quotient. “Scream” is funny, “shout” is not. “Cry” is funny, “weep” is not. On the other hand, “collapse” is funny, while “fall” is not.

These thoughts have been on my mind of late. What is the best way to make something funny?