Of course (I think I should have pointed that out in my first post), but physics/math/etc also take a long time to learn properly, so the time required becomes much less relevant.

I do not mean that one should necessarily learn a new language instead of learning math - although I might say that if you already know a lot of math (enough to get significant benefit to your thought processes), it might be useful to spend some time learning something that trains different aspects of mental processing (like learning a language). If I had to speculate on what any specific benefits might be, I would suggest that it comes from having more than one independent lens through which you interpret the world/more than one basis for your thought processes, and the benefit to mental flexibility you can get from switching between them (I'm not sure if I am properly communicating what I mean by that though).