A selfie with musical expression in the background. An attempt at heuristics

A selfie with musical expression in the background is a metaphor. We take a selfie to see a reflection of ourselves. However, the photograph also enables us to see what surrounded us and what we did not really pay attention to. Let us try to capture the essence of expression in such a metaphorical selfie. We will need additional mirrors: a mirror of language and a mirror of music, as well as a strong (logical!) insight into the real manifestations of language (speech and writing) and the real manifestations of music (sounding music – musica sonabilis and written music – musica scripta), into the relations between the manifestations of language and the manifestations of music, and into the differences between them, and finally into what and how they can express (we can express through them).