Well, it's sneezes that do it for the Frog
My poor allergy-prone cousin came around the other day, and shortly after stepping through the door was beset by sneezing (I was going to write "beset with sneezes", but that just conjured up an image of a gang of sneezes roaming the hallways and attacking the house-guests with coshes). Anyway, the Frog thought that the Great Sneezing Show was entirely for his amusement, and laughed uproariously after each sneeze. And in fact, it was so hilarious, that he broke his own '3 strikes' rule (i.e. if a thing's worth laughing at, it's only worth laughing at 3 times). He was even prepared to laugh at the fake sneezes Hubs and I performed with varying degrees of pantomime theatrics. I think he likes the sound more than anything else (he couldn't see my cousin during the genuine sneezing episode, and he still thought it was pretty darn funny). I've also noticed that he likes fricatives, like 'sssss' and 'zzzzzz' ("zipper" is a word I can say to make him smile). Oh, and of course "shhh" and "zhhh". So perhaps it's no great surprise that the sound of a sneeze appeals to him: Aaaaa-CHHOOO!
At least he'll be entertained when flu season rocks around.