The official language of Italy is Italian. In some border areas, besides Italian, French is spoken (Val d’Aosta), as well as German (Alto Adige), and Slovenian (Friuli Venezia Giulia).
In big cities you will have no problem communicating in English, especially if you go to places with a strong tourist influx (like museums, restaurants, large shops).
The situation is different in small towns. Here you might have more than one problem communicating in English and therefore you will have to rely on technology. One piece of advice we can give you is to have a good translator installed on your smartphone, Google Translate is fine. By using the translator you can interface with the locals in a fast and effective way.
Luca Signorelli, CC BY-SA 3.0, via Wikimedia Commons