Most of the kids today in India learn English and Hindi in primary schools and also manages mother tong (if different) and or a local / state language to some level. There are many benefits of knowing an additional foreign language, benefits being “cool” in front of friends or considered intelligent being a polyglot and also several economic and social befits over a life time.
Some facts and figures from Wikipedia on different languages are: (Top 5 Languages)
***So a person knowing these 5 languages can speak to almost every second person in world. ***
(One can communicate with 3.5 Billion People out of 7 Billion world population.)
Now, with Hindi and English covered in schools, Spanish can be a choice of a foreign language to start with.
There are lots of commonalities between English and Spanish script. Also Spanish is similar to Portuguese and one who knows Spanish can communicate with Portuguese with ease. Learning other languages like French or Italian will be much easier as these languages have similar vocabularies, with many words derived from Latin, and almost the same grammar.
For similarities / overlapping between languages refer to http://en.wikipedia.org/wiki/Lexical_similarity#cite_note-2 and http://how-to-learn-any-language.com/e/languages/overlapping-languages.html
On the other hand Chinese and Arabic languages will be tough to learn for kids (and for grown-up also) as they are not at all related to the English script. Many of the pronunciations are tongue twister and better learned through formal training and courses.