Well, let me take a shot at this:
Broccoli raab is a Brassica rapa like mizuna, turnip, and bok choy. It is an Italian vegetable, and there are various names for the subgroup. Other Brassica rapa may be in the chinensis or pekinensis groups and there are others. You can sort them out on [url=https://www.plantnames.unimelb.edu.au/Sorting/Brassica.html]the University of Melbourne's Sorting Brassica Names Index[/url] but it may take awhile
Broccoli is one of the Brassica oleraceas. It is actually more closely related to cabbage than to broccoli raab. A sprouting broccoli is just a broccoli that makes a lot of buds along the stem and not much of a "head."
There are quite a few common names for broccoli raab and it might be a lot less confusing
if it wasn't called "broccoli" at all! I think you might be happy with following a stir-fry recipe for it but I don't really know how this vegetable would be prepared in Italy.