No, you don't, but it certainly wouldn't hurt if you were familiar with the basics. If you don't speak or understand Italian, your best bet for jobs is at private schools run by native English speakers. You'll find more of these popular tourist destiinations and big cities like Rome, Milan, Turin, Florence and Naples. If you can, take a beginners or travel Italian course to make it easier for you initially, then immerse yourself in the culture and language once you get here.  Italian is a difficult language -  like a modern version of Latin, and learning it is a humbling experience. But you WILL learn, and it will make you a better ESL teacher because you will be able to appreciate foreign language learning from the student's point of view.