Best programming language to use?

Just getting into Arduino's and robotics. I was thinking about just using the Arduino language, but would it benefit me to learn C++ as a whole as well? I know Arduino is based on C++ but I don't know how much overlap there actually is.

I've seen python used too. If you were starting out, but wanted to biuld a large and solid foundation, where would you start?

P.S. Should I take some engineering courses? I am happy to jump into ENG courses at my university. Can you recommend specific topics/courses?