Why do you burp?

Answer 1

You burp when you are 'gobbling' down food , at the same time you are swallowing air, not breathing air, that air has to leave the stomach, so after a [very] short period of time it travels up your gullet/oesophagus and the air escapes from your mouth. This is what causes the sound of a burp.

You can make artificial burps by 'pushing' your throat in (without your hand) or practically swallowing the air (not the saliva - 99% water , mucine and amylase-)

X
Burping, also known as belching, ructus, or eructation, involves the release of gas from the digestive tract (mainly esophagus and stomach) through the mouth. It is involuntary, and it is usually accompanied with a typical sound and, at times, an odor.

Belching is typically caused by swallowing air (aerophagia) when eating or drinking and subsequently expelling it, so in this case the expelled gas is mainly a mixture of nitrogen and oxygen. Burps can also be caused by drinking carbonated drinks such as beer, soft drinks, or champagne, in which case the expelled gas is carbon dioxide from the drink itself. Common Diabetes drugs metformin and Byetta can cause belching, especially at higher doses. This often resolves in a few weeks. Belching combined with other symptoms such as dyspepsia, nausea and heartburn may be a sign of an ulcer or hiatal hernia, and should be reviewed by a physician.

The sound of burping is caused by the vibration of the upper esophageal sphincter as the gas passes through it. The current Guinness world record for the loudest burp is 107.1 dB, set by Paul Hunn in 2008. (This would be noticeably louder than a chainsaw at a distance of 1 metre.)
A burp is an escape of stomach gases through the mouth. Some people are prone to burp more than others. A possible cause of excess wind could be your diet?