It's almost never self-contained. At the most basic level, if you don't know the language, writing is just meaningless scribbles. Scales and chords have no particular meaning by themselves. Associating a major scale with happiness and minor with sadness is something you learn.
We've got this weird situation where people can't just look with their eyes and hear with their ears. For them it's all about thinking. They want something to think about. They want a story/joke/explanation. For them the action is all in their head.