It would be pretty easy to come up with criteria that support or dismiss benefits of learning two languages, or any pair of specialties at all given inherent tradeoffs

For example, folks who learn programming languages early and intensively have a certain analytical advantage. But this is not a positive in all situations. We all have limited energy/time/focus, so each area we learn necessarily costs us in other areas.

And that’s great. We should develop strengths and build on them. Our lives are short and our attention is limited