Even outside of the states, Spanish is one of the most widely spoken languages in the world; the ranking is apparently in dispute as I found numerous statistics. Most Latin American countries, those in Central and South America speak Spanish with an ever increasing amount of people in the United States. That is almost an entire hemisphere full of a language. And then there is Spain as well, while that Spanish may be slightly different than the Spanish in Latin America, Spanish it still is.
There are an ever-increasing amount of reasons why people should learn Spanish. Not only because of the amount of people who speak it but in a more selfish way it is becoming increasingly valuable to speak a second language professionally. The problem is that people in the United States tend to be more than a little arrogant in their thought that English is the most important language and they simply don’t need to speak anything else.
Being bilingual gives one opportunities to live and work outside of the country that would be unavailable otherwise. It gives one options. And given the large amount of counties in which Spanish is spoken it gives one a lot of options.