Merlin makes grunty little piggy sounds - especially when he is all sleepy and snuggling down for a long nap. He is also quite good at facial expressions too. It is like he is using "The Force" on us to get what he wants (which is usually food).
How about belching? Duncan is without a doubt, the rudess corgi I've ever seen. Always belching or burping. I swear, sometimes I expect to come home from work some night; see Duncan on the couch, in underwear, paw inside (like Ed Bundy) with a remote in his hand channel surfing; looking for "Corgi Babes in Outspace"
Radar has so many different sounds that he makes. When he is guarding something it is a series of low & high grumbles and a look he gives that would stop a clock. We have a speaking trick that he does. I will have a snack and tell him to speak and of course it is the Corgi bark. I soften my voice and tell him to speak "nice" and he tones it down a bunch, then I nearly whisper speak "nice" and you just feel warm air and a little woof coming out of him. Took lots of patients for that trick! Yeap!! Radar can belch with the best of them. Sometimes it is a deep beer belch and other times it is almost a hick-up!!! Once in a while he has a backfire instead of a belch. That is funny....he will look at his stub then look at you as if to say "What waS THAT!!!!