Bring an Italian phrase book if you can't speak it
Aosta is a touristic area but probably not as popular as some other nearby places such as Courmayeur. So, here naturally you will find less people who know English or French, compared to for example Courmayeur (which is a ski resort town closer to Mt Blanc). Take an Italian phrase book with you. The main 2nd language spoken here is French, and then English after that. Learn some Italian simple phrases before you arrive, or you might find yourself lost and unable to ask for directions or unable to communicate about your meal.