Can you burp?

ELB and myself were eating with the kids when out of no where a unique sound came abruptly. It was the sound of a loud belch that sounded like a mixture of pain and pleasure with a pinch of train wreck. I thought it was one of the kids, but to my surprise it was my lovely bride. She has been known to keep up with my friends with the belch factor, but this one took the cake. I know some of us can do it on command, but is burping a learned trait or can we all do it? Can you burp on command?