Which courses would help before joining an MBA school ?

You are right- a foreign language could be something both useful and fun.

Duk- As for your comment about Americans studying foreign language in school (high school and college), please do not have the wrong impression. In truth, most students take a year of Spanish in high school, and two years in college, however it`s more like a required ABCs course, emphasizing elementary sentence constructions, which most students forget a year or two out of school. The fact is, (I myself was a linguistics double major) less than 10% of native born Americans ever actually gain "coversional" proficiency in any foreign language. Please do not be misinformed because, unlike our European counterparts, the vast majority of American are indeed monolingual.

You, on the other hand probably speak Hindi as your native tongue and clearly have a superior command of English. IMHO, further refining your English skills alone will make you stand out from other classmates this fall.

Hope this helps.