dolli, gnocchi and cavatelli are very similar, and you're right, they're from different regions of italy. but there arw differences.
gnocchi is from northern italy and is a softer pasta, while cavatelli is from the south and is a more traditional pasta (as far as americans would consider pasta) that is more "al dente".
as andy mentioned, gnocchi can be made and often is described as potato gnocchi. again, much softer than all flour pasta.
both are cut finger rolled/pressed, but cavatelli tends to be longer, gnocchi shorter. maybe the latter is because it's softer and stretches less, i don't know. but it's a thing to behold to see a nonna and a mama or two crank out either pasta with a cut, press, roll, and push to the side of a floured counter.
i love them both because they'rr kind of "meaty" pastas that go well in particular dishes where other pastas would get lost or just wouldn't work.
oh yeah, i just remembered 2 more butchered words. fazool, as in pasta fazool, more properly pasta e fagiole - pasta with beans.
or rigott, aka ricotta. and of course, we call it cheese, which it ain't.
in nomine patri, et fili, et spiritus sancti.
Meh nom eh noh...doot dooooo do do do.