Most of the merchants, hotel registration staff, and waiters will speak English. They are accustomed to working with tourists. Other staff may not.
Costa is an Italian cruise line. Announcements will be made in Italian plus several other languages including English. Many of the passengers will not speak English. Costa excursions are available in English.
English will be spoken by merchants in all of our port cities.
Even if you have no prior background in Italian it is considered polite to make an attempt to use a few words of the local language. At the very least you should try to use their basic greetings such hello, goodbye, thank you, and please. This doesn't take much effort on your part.
"Hello" or "Good-bye" (informal)
"The bill, please" (at a restaurant)
"Il conto, per favore"
Words you May Encounter on a Menu
"before the meal" (appetizer)
"first course" (usually pasta without meat or soup)