I have tried to encourage Cadets to take a language and to attempt immersion to actually
LEARN a language. Unfortunately, the US does a horrible job teaching languages emphasizing the reading and grammar of a language over the actually speaking of a language. Personally, I think Spanish is a good language to learn and there is a pretty good chance of using it at some point in a military and a civilian career.
First, there’s a good chance that there will be some Spanish speaking soldiers working for you at some point. No, you don’t need to communicate in Spanish, but it’s not a bad thing to have in your hip pocket in such situations.
Second, you may well encounter Spanish speaking foreign soldiers. In Special Ops I worked with Mexican, Panamanian, Colombian, and Venezuelan (when they were our friends) soldiers. I got by without knowing Spanish, but it would have helped.
Third, you never know when you will be thrust into an assignment where a language will help. As an Aviation officer I found myself in the Sahara Desert as an UNMO (UN Military Observer). It was frustrating to always have to rely on a translator when I interacted with senior officers in the Moroccan Army (French) and the POLISARIO (rebels who spoke Spanish as their second language).
Quick “war story”. On my last meeting with the Moroccan commander in my sector he invited me to lunch and told me to leave my translator. I was initially confused, but assumed he would use his translator for the meeting. He greeted me in perfect American English.

His children all lived in the US and he was fluent in English along with Arabic, French, and Spanish. He laughed and said he used a translator to give him an advantage in our meetings.
I included that tidbit in an INSUM for my replacement.
My point to that story is that there is much they don’t teach you in ROTC or the SAs. You never know what kind of off the wall assignment you’ll find yourself in or when a language will come in handy.
As a follow on, I have been able to use my German a little in my civilian career, though much of it is forgotten. Spanish would have been more useful. Then French, Korean, Chinese, and Japanese in that order.
Yeah... back to Korea. Who’d have thought.