I stayed 8 years in Hyd. Most of my Andhra friends were able to understand basic Kannada. Its not French and Chinese.Not sure how closely Mallus understand Tamil but I'm aware their script is quite similar just like how Telugu and Kannada are. I'm Telugu and even though I can read Kannada a lil bit, the meanings of their words are entirely different from ours. I can understand Tamil better but that maybe because a part of my extended family has Tamil lineage
Whatever fits your version but we believe in the concept of "Unity in Diversity" which has worked very well so far and we're able to do well than most homogeneous countries