Italian Translator App

Here is a current thread you can follow.
https://community.ricksteves.com/travel-forum/italy/offline-app-for-translating-italian

In addition to the suggestions shown in the other thread, you might also check your local Library to see if they have language courses that you can work on before your trip. I really like the Pimsleur series. You'll find it much easier to function if you have a few basic skills in the local language, rather than referring to your phone every time you need something.

I could go along and be your interpreter.

Seriously, what Ken advised is a great idea. There is no substitute for having a few words and phrases. If you are worried about menus, reading signs, etc., most of it you can noodle through but using Google Translate or a dictionary app can help. I like one from Xynotec for when i need to to a quick look-up.

Our Italian friend (who speaks five languages fluently!) always suggests Reverso. We will be using this on our trip. It also has offline capabilities.
http://context.reverso.net/translation/mobile-app/
Google Translate is fine but it often 'mistranslates' thus making communication a bit difficult (and often funny!) I've used both Reverso and Google Translate in my work (I work with people who speak Spanish, Farsi, Russian, etc.) and the Reverso translation--by far--is more easily understood.