Creating your own language. For example, Toki Pona has just 120 words.

Some people make do with eight:

http://en.wikipedia.org/wiki/Brainfuck

But it can't be too hard to create a second language that maps onto a more common language. What would be hard is to design a 120-word language that you could teach someone, such that they could learn English a few years later and still get a decent score on their SAT. But that would be cruel.