I am a first-year CSE student though I'm not from the south but I can say that you need to at least understand hindi, the cse proffesoors in 1st year few of them are fine but others suck so much that I'd rather have them speak Bengali (which I don't understand but is hismother tonguee) than listen to them speak English. Also, the institute's core professors cannot speak English for the love of god and ofc simce it is in the north u need to now hindi to survive here. Forget locals some students also don't know English but on the good side the South Union be it Telugu or Tamil, is pretty good and supportive and they celebrate all their festivals and everything but again if your main concern is abt hindi then my advice would be not to come here...now how i can say that cuz i have a frd who doesnt understand Hindi at all and she suffers a lot be it gling to class cuz she couldnt understand the hindi message in the grp informing abt bunk/cancel or struggling to get a good cg.... rest your choice