If you are going to a business major, what language would be best to learn?
It's very nice to hear that you have the ambitious to advance your career in business. I agree with Steve that if you can speak English, basically, it's very easy for you to go around the world in Science and business.
I will say your territory decides the language you need. If you will have a lot of business connection in Japan, Korea, or China, it will be very helpful that you can speak their language. I grow up with Malay, English and Chinese. It makes me very comfortable when I moved to Taiwan, as I can speak Chinese. When I moved to Japan, I started to learn Japanese. Fortunately, their are from the same root, my native language (Chinese) speed up the process of learning Japanese.
My suggestion is, you can choose to learn a third language that you like. Ideally, Japanese or Chinese, as you already know Spanish, it is more easy to adapt to European language, while learning Japanese and Chinese will take you a much longer time.
To add to some good answers already about "popular" languages (I work for a company whose "global" language is English), it can depend on the industry. For example - for fashion and luxury goods, FRENCH and ITALIAN might be useful, or if you are working in the Aluminum industry RUSSIAN could be useful given the source / scale of resources in that industry. For tech - CHINESE / JAPANESE might be useful as so much of global tech development is happening in Asia-Pacific region, and ARABIC for the Oil industry (or you want to live in Dubai to avoid tax HaHa!)
Also - your location could be important - if you live near a border (France / Germany) - then closer travel across borders could be helpful
Just some thoughts
Brazil speaks Portuguese so it will be easy to adapt your Spanish. Russia of course speaks Russian.
The problem with India and China is there are so many languages in use. Popular languages in India are 1) Hindi, 2) English, and 3) Bengali.
There are as many as 292 living languages in China; Mandarin is spoken by 70% of the population. Interestingly, China has one of the world's largest population of English speakers—that is, they have between 250-350 million who speak English at some level of literacy.
What I've found is most business people speak English much better than Americans can speak their languages. But they really appreciate that you try. Being able to say Good morning, Thank You, You're Welcome, and similar basic phrases makes you a better international traveler. .
Wendy Ramirez Attal
Hi ! It is great that you already speak Spanish & English. I speak Spanish, English and Portguese and have been able to use my language skills with the Latin American markets as well as Europe.
The field that you are pursuing could dictate the language you choose to study. Any additional language skills and cultural knowledge can be beneficial in whatever area that you pursue