I am looking for a functional language that is basically dynamic programming - i.e. one where functions are first-class objects - but where all function calls are asynchronous by default; i.e. you define function X(a,b) = (Y(a)+Z(b)), and when X() is called, it sees it is waiting for the return from two functions, runs one in the current thread, and spawns a new thread to run the other.

The future is very much parallel processing; multiple cores, multiple machines, the internet of things, etc. and I was wondering if there was a language specifically designed to make this kind of parallelization easy.

I currently have only used imperative languages (c, php, java, ruby, etc), so I don't know anything about what kind of functional languages are available.