Like Milan, most people speak English in Venice. That’s probably because of the massive amount of tourists - I’ve also heard people speaking French, Japanese and German. A lot of the signs are in French, German and English, but when they’re only printed in two languages, it’s Italian and English.
It helps to know some basic phrases, though. Gratzi, scuzzi and bounjourno are pretty obvious and go pretty far. Quanto means “how much?” but you have to be careful with that one because if you ask in Italian, you’ll get answered in Italian.
Some other words I’ve picked up are ponte (bridge), piazza (square) and calle (street/alleyway). Street signs are the easiest way to pick up a language, in my experience.