Help Me Choose a Language to Learn.

I live in the United States. I am fluent in English. I know nothing of any other language. I would love to know what the most useful language will be in the future. I'm going to be dual-enrolling soon at a local university, and I wanted to take a class which is unavailable to me.

Can you suggest a language? The only classes currently available to me through my high-school are Spanish and Latin.

Learn a language that you will actually be able to use. Like if you live near a Vietnamese or Chinese store, learn some Vietnamese or Chinese to speak with them. If you have some Polish neighbors, learn some Polish. Don't learn some fucking language nobody within 100 miles understands like Guaraní.