[allenu]

I feel like in this particular case, the first step is to recognize there's a "problem" at all. I don't know the person in this story, but it seems like to them, communication is not that important. Maybe the most important thing for them in their work is technical achievement. (I've definitely been in that boat before.) As a result, they are likely never going to work on the communication aspect.

This is like the quote of "Don't tell me what you value, show me your budget and I'll tell you what you value." Before you go and try and improve yourself, it's good to be honest about what you value and what your goals are. If what you value is moving up the corporate ladder, then learning even more about C++ is not going to help. On the other hand, if it's to be even better technically, then go for it. If you value improving your business all around, then the communication angle is a better place to spend your time.