most of our "sausages" derive from Roman cooking, and haggis can be traced to such a recipe. As can scrapple. Obvoiusly local ingredients change flavors and local cooking methods do to. But a frugal people don't waste any part of the animal so that which was too tough or too small (little strips of meat) were ground up with meal and stuffed into something. Offal (inards or organs) are quite wonderful fresh. In America, often the liver is frozen and that really changes the texture and the taste. But Liver with bacon and onions, or with a tomato sauce is quite wonderful, medium rare.
Kidneys are not done much in the US but a few restaurants can serve them and my mom from British Columbia introduced me to them early in life. A steak and kidney pie is the richest beef stew you'll ever eat. awesome. and on it goes. properly prepared it is all quite wonderful. Eel anyone??