Spoken Kannada
Learning Kannada will be completely enriching, refreshing. If you are person supposed to be in Karnataka or have to travel Karnataka a lot then Learning Kannada is the best way to make new friends from that locality. You can help them also about your native and culture that is how great societies are made, by learning and sharing.
If you don't learn Kannada, you will always feel as a non-native, you will miss important cultural significances of all Kannada speaking areas in the country.