Even broader, communication is the art and language is one of many media available. However, communication happens only on the part of the recipient, thus meaning is only assigned by the listener (or viewer or taster etc.) guided by genetics, social interaction, weather, mood, time of day, etc. The beauty of music is how it is so undefinable what the definition or rather meaning of it is, however the effect it has on us. This list is direct evidence that we share that. I think BMG put it in perspective best when we were talking about Aphex Twin's Picture Disk (HMNE/Joyrex J9ii, I think... HP can help me out w/that one ;). The conclusion was that it was so incredibly aggressive and unrestrained that it invoked so many emotions that it became frustrating. Not that the emotions were frustrating, but rather that there was nothing that could quite top it (musically), nothing that would surpass that particular degree of provocation. Bringing the point that the effect of music is some thing in tune with (bad pun) language, but by way of a different media and thus a different type of cognitive thought. Language is interesting, but music is seductive, provocative, aggressive, etc. more to the point emotionally inciting.
A picture is worth a thousand words. A song must be worth at least 1,000 times that. Scott Sorry about the rambling, but I'm listening to Autechre (ep7)...