Supercollider is a popular choice! If you're interesting more of a survey, I wrote a blog post a few months ago where I compared music languages by writing the same sound in each one:
https://www.safaribooksonline.com/blog/2014/11/07/making-com...
I looked at supercollider before you answered and found the syntax kind of attractive. Sort of scala-ish, though maybe I am misremembering Scala from that one programming test.