Actually, if you're an adult English speaker, learning foreign languages is probably not worth its opportunity cost. It takes an enormous amount of time and effort to learn a language well enough to do anything useful or productive with it, or even just to be able to talk to native speakers in a way that won't be annoyingly incompetent.

What's more, for just about any language there are huge numbers of native speakers who speak professional-level English, including natively bilingual kids of immigrants, so you're not developing any rare and precious combination of skills. (There are exceptions, such as e.g. knowledge of some languages combined with a security clearance that's hard to obtain if you're not a native citizen, but they are few and far between.)

Of course, if you find learning languages a fun hobby, go for it. But unless it's a greater source of fun and enjoyment than other things you might be doing, it's quite pointless. (And I say that as someone who can find his way around in at least five different languages.)