The tongue is one of the most highly prized offals in Southeast Asia. If you've found a recipe for tongue and you go to the meat shop to buy one, you'll find that the meat is labeled as “ox tongue” in some cases and “beef tongue” in others. Both labels refer to the same thing. The difference in the terms used to describe the meat is based on farming history and practices.
Cattle—or cow as we non-ranchers call the animal—has played a significant role in man’s life for a long time. Cattle was so important to a man that there was a time when it was considered currency and the animals were used to buy, barter and pay debts. Cattle has also been a source of food for just as long. Not only do we eat the meat, but we also drink cow’s milk. From the cream, milk, butter and cheese are processed. But the role of the male cattle in farming has changed over the centuries. And it is that role that accounts for the terms “ox tongue” and “beef tongue."
Back in the Middle Ages, the cattle was both a field worker and a source of food and clothing. “Ox” was the term used to describe male cattle while “cow” referred to the female. Male or female, cattle were used to plow the fields, pull carts to transport food (and people) and lift heavy farming tools. The females supplied the farmer with dairy goods and what he and his family could not consume was sold. The animal skin — leather, we call it — was used for clothing and footwear. In other words, back then, the tongue of any male cattle was “ox tongue.”
Over the centuries, farming methods changed. Someone discovered that by castrating male cattle, it became more docile and, therefore, easier to work with on the farm. While terms vary from region to region, generally, castrated male cattle became known as “ox” while those that escape castration were called “bulls.” If you’ve ever wondered why the animals in bullfights are called bulls and not oxen, it is because these male cattle have not been castrated to retain their natural aggressiveness.
So, when you go to the meat shop looking for "beef tongue" but find "ox tongue" instead, does that mean that the tongue came from a male animal that was not castrated before slaughter? Not necessarily. Cattle meat—whether from a castrated male, a male that was not castrated or a female—is beef. Whether the tongue is sold as "ox tongue" or "beef tongue" is more a matter of commercial usage than any real distinction in the animal from which the tongue came from.