I second this. Whether you learn Spanish or French or Italian, simply knowing another language (aside from the personal pleasure of having new friends on the internet, new restaurants or clubs to hang out at etc.) means that you can look at more job offers. If ever the situation should come up that you work for a company with international branches, and they want to send somebody abroad, you have an edge. If foreign exchange students arrive at your local high school or university, and they want tutors to help them integrate and get to know your city, you can offer help and maybe then get offered something else.
It means you more likely to visit that country because language is no longer a barrier. (I know, if you pick France, it’s across the ocean - but Canada you can drive to!). Maybe you come for a guest term at the university, but find a wonderful job oppurtunity that you never thought off at home.
Everything’s possible, you don’t know beforehand what might happen, but with an additional skill, you get an additional card in the game, so to speak. (and be glad you don’t have to learn spanish in 6 months because you have been ordered to go to Mexico by Headquarters! instead, you can simply choose to your liking.