Many Italian universities and colleges in Italy, offer courses in the Italian language, which might be incomprehensible for most of the international students, especially those who don't speak Italian at all. Sitting and taking language exams to prove their Italian proficiency (if they are applying for a university that doesn't teach in English) is a must for foreign students.
Although some educational institutes teach in English and many more are yet to adapt to it, for that as well, you will have to appear for an English language exam. And after arriving in Italy, you can seek admission in an Italian language school for learning it.