This is simply a durum wheat semolina pasta extruded from a special die and cut very short into the shapes of letters of the alphabet. They are used in soups and often made with extra gluten for children.
When I think of alfabeto, I am reminded of when I arranged the wedding meal for my stepson and daughter-in-law. I decided to add their initials and some love hearts to the soup and had to go through hundreds of packets of alphabet pasta to get the letters ‘S’ and ‘G’ (Sarah and Granby). The disappointment came when only a few people noticed as they reached the bottom of their bowls of soup.