Actually the language used to describe the recipe might be. it's just that the recipe itself is not, the fact that you mix 2 cups of this with 1 cup of that and bake at so many degrees. So language that's a plain listing of that in a standard format isn't copyrightable, because it's just a straightforward way to list the uncopyrightable recipe. But if you use especially creative and unique language to describe a recipe, that particular language might be copyrightable. The recipe as a recipe is not; the language used to describe it can be, if it's an unusual or creative way to do so. But someone can most definitely always use their own language to express the same recipe -- the same ingredients in the same amounts combined in the same ways, is not copyrightable.

This has until now seemed like it should also mean that the API as API is not copyrightable, and a straightforward implementation of something like `min` is also not, as it's just the only reasonable way to implement `min`. But an especially clever or creative algorithm to implement a part of an API might be.