I agree with genecroix, but music is a phenomenal way to teach students a treasured art. I play the violin myself, and I can tell you, it is always exciting. Getting a new piece and turning it into something new is a way to get people into trying out an instrument and then maybe creating something new from it is a way that kids can experience this.
Music is very similar to all language courses, requiring skill and mostly memorization. With the patterns found withing music, there is absolutely no reason why it shouldn't be considered a language course as well, since people can clearly communicate through this method. The art form is a major necessity of humans and should be rewarded as such.
Creating music is certainly art, but memorizing a song does not invoke the same amount of creativity and self expression. If the music class were to be considered an art class, it must be one where children either write their own music or at least put their own spin on an existing one.
Music is not a language by any means. It's a form of communication, but in the language you already know. Certain tones and alignments of notes don't have definitive meanings, it's all subjective. Writing what you sing is essentially just your own language.
The challenge of a language class is that you are forced to express your ideas using sounds and letters you've never once associated with the things you know. You have to structure your thoughts in a different order, you learn new expressions, and you're suddenly open to understand and interact with an entire culture that was once isolated from you. Music has it's purpose, but it can't replace a language course.