Tarz wrote:This translation will help: SONO VEGETARIANO...
the rest of the translation could help if you know ho to pronounce it
but "vegetariano" doesn't mean vegan ... it means vegetarian, so you don't want to use that word. you have to say "vegano"; but if you go to a restaurant or supermarket, they wont necessary know what a "vegano" is and what the difference between a "vegano" and a "vegetariano" is.
that said, living in italy as a vegan is extremely easy because the mediterranean cuisine is heavily based on grains, fruits and vegs. this reflects on choices you have at restaurants, supermarkets, minimarkets, outdoor markets, etc.
if you go to a supermarkets, (almost) all packed food is labelled both in italian and english.
if you go to restaurants in turistic places like rome, they should have menus in english or at least a waiter that does speak some english. if that isn't the case you can explain, or hand the waiter a piece of paper with what tarz wrote (changing "vegetariano" into "vegano") and ask or write: "cosa mi può suggerire?" (what can you suggest?). he/she'll come up with plenty of options from rich salads to pastas with so many different kinds of sauces (just remember to specify not to add any cheese (formaggio) on it, because cheese is a huge thing in italy and everybody, apart from vegans and extra terrestrials, puts it on pasta.
you can also go to any pizzeria and ask for whatever pizza you want, and tell the waiter you want it without "mozzarella". just choose any without meat or fish or eggs on it. or you can ask a pizza with the ingredients you want. i allways ask for "pizza con (with) rucola (rocket), funghi (mushrooms), e (and) pomodori (tomatoes) senza (without) mozzarella (mozzarella cheese); something i often ask for as well is "pizza marinara" (tomatoes, garlic, oregano, oil).
in essence ... you'll be fine
enjoy your holiday and let us know how it went, once you're back