It really depends on what you mean by "South." It's a bit subjective. For example, if you're in Jammu, Punjab would be considered south. But if you're in Russia, all of India is south. Could you clarify which areas or states you have in mind? By the way, I'm studying at IIIT Hyderabad, and I'm from Patiala. It's up to you to decide if that's considered south based on your perspective.
At IIT Hyderabad, you'll meet Indian students from all over the country who will assist newcomers in settling into campus life, no matter where they're from. If you're curious about specific regions, students come from various parts of India. IIT Hyderabad isn't dominated by students from the south or the north. The ratio of students who speak Hindi to those who speak other languages is roughly 2:3, so there's a good mix of people from different backgrounds.
The student mix at IIT Hyderabad can vary each year. In my batch, about 25% were from Andhra Pradesh or Telangana. The rest came from various parts of India. If you're worried about fitting in, don't be. Students from all over the country attend, so you'll likely meet someone from your area. However, I really recommend chatting with folks from different backgrounds. It’s a great way to experience new cultures and perspectives, which is one of the coolest parts of college life.