Tongue is often seasoned with onion and other spices, and then placed in a pot to boil. After it has cooked the skin is removed. Pickled tongue is often used by the preparer because it is already spiced. If cooked in a sauce, it can then later be reused as a sauce for meatballs or any other food item.
Another way of preparing tongue is to scald it in hot water and remove the skin. Then roast the tongue in an oven, using the pan drippings to prepare a gravy.