Cow's tongue and organ meats in general are FANTASTIC foods to consume. Very healthy and very lean.
I regularly eat cows liver and cows heart. If you trim the fat off the heart, it's extremely lean and has a taste very similar to steak.
Not only that - they are dirt cheap. I get all my meat from a local farmer. He sells me the liver and heart for 3-5 dollars a pound. That's for organic grass fed beef too.