I have, to date, listened to five of my Jewish friends tell horror stories from childhood that involve opening the fridge door and chancing upon a whole cow's tongue, put there by their well-meaning mothers. Five friends, all Jewish, does not amount to statistical rigor by any means, but their anecdotes sound like something out of a Philip Roth story.
The innocent child opens the fridge looking for a snack of some sort. The light flickers on, then off, then on again. What should appear before their eyes but a gray and flaccid tongue, raw and absolutely enormous sitting whole on a platter, stippled with papillae and marbled with fat.
Oh, the horror! The sight of the dreadful tongue makes them forever prejudiced against the organ. Squeamishness aside, the tongue is such an appealing cut: tender and fatty, and delicate in taste (unlike kidneys or liver, for instance, which have a more distinctive flavor). This is because the tongue is a muscle and therefore tastes like flesh rather than an internal organ.
Tongue is good whether it comes from a lamb or pig, calf or cow. That list is ordered from smallest to largest. A calf's tongue is half the size of beef tongue, only milder in taste and slightly more tender. You can confit a tongue, braise a tongue for stew or tacos, or even pickle a tongue.
Soaked in a brine for a week, then simmered until it's extremely soft, the tongue is good either hot or cold, and both ways, served with horseradish and mustard.
During the summer, I keep the tongue on hand for a sandwich. Like corned beef or pastrami, the thin slices of tongue are so rich and satisfying that it's perfect between two slices of rye bread. All it needs is some horseradish and mustard, and maybe a dill pickle.