[synth3tk]

If you were the only programmer, or you only had two student programmers, then yes, I'd suggest explaining to the mentor why you chose that language, and stick with it, while teaching the other student at the same time.

But with 8? You pretty much need to stop worrying about what YOU think would be best for only YOU, and start thinking about what would be best for the TEAM. As Don pointed out, building the robot is only the tool used to build the future leaders, innovators, and businesspeople of the world.

By the way, one way to convince your mentor to use C++, is to show that you're willing to teach the others how to use that language. And before you say anything (I've read your posts regarding teammates), don't underestimate your teammates. You've still got 5 weeks. That's plenty of time.