Boil the tongue until it is tender throughout but still firm, having added the oregano, a teaspoon of salt, and a teaspoon of pepper to the boiling water. Cool to room temperature.
Remove the tongue from the water (reserve water and set aside for later) and peel the skin off the tongue (discard skin). Cut tongue into fine slices.
Heat the oil in a cooking pan over high heat. Add the tongue slices and brown. Remove from the pan.
Lower heat to medium and add the onion. Cook and stir until the onions become translucent. Add the garlic, bell peppers, carrots,olives, scotch bonnet pepper and cook and stir for a minute. Add the tomatoes and tomato sauce. Cover and cook over low heat until the tomatoes are soft.
Add water that you had set aside and simmer until it is reduced to a thick sauce.
Return the tongue slices back to the pan. Mix well and cook for a minute.
Stir in cilantro leaves and season with salt and pepper to taste.
If you wish to cut on time, boil the tongue in a pressure cooker. It takes about 15 mins. in a pressure cooker, as opposed to almost 40 min to an hour in a regular pot.If you wonder whether you can cook this dominican recipe for cow tongue in crock pot, the answer is yes. Although I haven't tested it, and this is something that you may have to try on your own