There is a programming language called sonic that is used to do audio programming. DSP functions are easy to do with sonic. This language compiles into c++ code; it doesn't have its own compiler. In this respect, it isnt a real language, but it isn't meant to be. It is currently under development by Don Cross.
update: i think this has sort of died out. I havent seen any activity on the page in quite a while. oh well, at least theres still SAOL