You can get by pretty well in most of Italy with just a few phrase-book words. Younger people, and those in hotels and tourist-related places speak enough English to be helpful when you reach an impasse, and Italians are naturally helpful and hospitable, so they will find someone to translate. When I moved to Verona, all I knew in Italian were menu words, and I got along fine. Remember that Italians speak with their hands, faces and a lot of body language, so they are easily understood.
I do suggest, however, that you shy away from more remote places in southern Italy until you have been there long enough to pick up a bit of language -- they are much harder to understand and Engish is less spoken (outside of Sicily, where everyone seems to have relatives in the United States.