what is a compiler

what is it? i know you type pretty c++ or w/e code and it converts it into computer language so computer knows waht we mean, how do they differ for different languages asides that they convert two different languages? (its kinda hard to explain what im asking) like if all it does is change what we do to computer language for any programming language, why can't we have 1 universal programming language

>>8
Moronic stupitude.  >>7 is right on.  If programs were only written for computers to read, they'd still be written in 1's and 0's.  That's a heckuva' lot easier for a computer to read.