Learn Mandarin. You can order from the menu they only give the Chinese customers.
I sympathize. It depends, I guess, upon whether you will go into some kind of import business. China is a huge exporter, and it would help in dealing with them. However, it is also making inroads into South America, and I am wondering if they are learning Spanish, in which case we probably should choose Spanish, too, because that is widely used here. You will need it to deal with your customers. But if the Hispanics, who don't want to learn English, start learning Chinese, then watch out and go for Chinese. Maybe you should just learn both.
Somehow I don't think I helped. heh heh
Furthermore, students receive Mandarin language and culture instruction with the goal of furthering our students' preparation for global citizenry.
So, I guess you need to buy some Mandarin instruction tapes.