Hiccups... are all the old wives tales true?

I'm sure you've all had a hiccup at least once in your lifetime. Though it usually isn't that bad a thing, sometimes it may cause discomfort and specially cause social embarrassment.

What really happens when you get a hiccup?
In the human body there is a muscular wall known as the diaphragm separating the thorax from the abdomen. When the nerve supplying this muscle is stimulated due to some cause the diaphragm contracts very quickly and with force. Due to this the abdomen swells and quickly sucks air in, causing the "hick" sound of a hiccup. So the problem lies in the Diaphragm and not in your throat.

What are the reasons for a hiccup?
A hiccup may be caused by eating too quickly, eating hot food or spicy food, drinking alcohol or carbonated drinks and even laughing or crying loudly. The usual hiccup that lasts for a few minutes is nothing to be concerned about.
But sometimes hiccups do arise due to medical disorders. Diseases of the lung and the pleura which cover it affect the Diaphragm and stimulate it due to their close relationship to it. Sometimes the stomach, other intestines, the liver and the gall bladder may become diseased and stimulate the diaphragm. In pregnancy, due to the contents of the abdomen being pushed on to the diapragm hiccps are frequently encountered. Rarely diseases affecting the brain can also cause hiccups.

Do smokers and alcohol drinkers get hiccups more often?
Yes, And also for people who eat oily/spicy food hiccups occur easily.

Saying, "ඉක්කයි මායි ගාලු ගියා, ඉක්ක දාලා මං ආවා" is supposed to make hiccups go away, is this an old wives tale?
There are a number of methods to treat a hiccup, to hold in breath for as long as possible is one of them. Even when you say that phrase quickly what happens is you are holding your breath.
other people try drinking water continuously, some put sugar on their tongue and hold it, exhale into a bag. If all these does not work,
1) Pulling the tongue out and holding it for a while
2) Closing the eyes and then pressing on the eyeballs for a while should help.
What happens in all of these instances is that the nerve controlling our breathing the 10th cranial nerve(Vagus nerve) is stimulated somewhat controlling the hiccups.
So you see it's not an old wives tale after all.
Further treatments that could be given by a doctor include carotid sinus massage, medication(Chlorpromazine) or in the rare case even surgery to divide the phrenic nerve supplying the diaphragm.