Learn whichever one you’re more likely to actually use or practice. I learned French in high school and college to the point I could listen to French news and (mostly) follow along and read simple fiction books.

As soon as I left that environment where it was constantly practiced and reinforced, my comprehension slowly decreased. With no one to speak it with and being unwilling to dedicate practice time to it, over the course of nearly two decades, I’ve forgotten nearly all of it.