One day in my high school philosophy class, the teacher gave us a list of different methods of expression and asked us to determine which ones constituted language. Among those that ended up in the "no" stack was music, since, we decided, it worked on a subjective level and couldn't relay concrete messages.
No doubt we were right. But even if music doesn't count as language per se, there are moments when it comes close — for example, the night when late jazz great Dave Brubeck visited the Orange County Performing Arts Center two days after 9/11.
That night, Brubeck brought an audience to tears playing a song on the piano. The song, "Nobody Knows the Trouble I've Seen," does have words — it's an old spiritual built around the refrain "Nobody knows the trouble I've seen / Nobody knows but Jesus / Nobody knows the trouble I've seen / Glory hallelujah" — but Brubeck, who died last week at age 91, didn't sing them that night.