Black radishes are not a common component of most people's kitchen.  On the other hand, they're one of the better stored foods.  I picked up several from Heritage Prairie Market in the fall and got around to eating some today in an easy to make salad.  Black radishes have a strong bite that needs to be tapped down.  Alter kockers used a bit of schmaltz (a/k/a chicken fat) to do just that.  Sour cream, or fancier, creme fraiche would also work.  I, however, took it on full bore:

1 large black radish, two small radishes, peeled and grated coarsely

Salt

Juice from 1 lemon

1/2 tsp honey

splash of olive oil

Salt the radishes and let them sit at least five minutes to draw out some water/crisp them up.  Combine the rest of the ingredients.

Note this recipe would work fine with turnips too.

Can you translate alter kocker?