it is myth that southerns don't know hindi. it is only tamilandu.
in kerala, karnataka, AP hindi is taught as 2/3 rd language upto 10th class. Almost all of the colleges offer hindi as a language in +2 .
if i'm not wrong hindi is recognised in AP as 2nd state language. in north karnataka even illeterate people don't find it difficult to speak with hindi s. in south karnataka it's bit problem. but don't forget bollywood films are equally enjoyed here as it is in hindi heart land.