Having concluded that language is the expression and communication of emotion, the total sphere of communication needs to be added to complete this discussion. Verbal (oral and written) communication is only one of the ways that we communicate our emotions. The two other major forms are through music and aesthetics.
Certain music conjures up very similar emotional experiences in us. An ominous song comes across as such to most listeners. Whether there is some objective trait or subjectively created cultural understanding in music that makes it sound dark and ominous we seem to understand the intent for the most part. We match happy lyrics with happy tunes, and angry lyrics to angry tunes. Music is an additional layer of emotional communication. In Celine Dion’s “My Heart Will Go On”, the feelings of longing are significantly heightened by the melody of the music. We like those sounds that resonate with our own feelings and emotions. We like love songs, we like soaring anthems, but we can’t stand a tune that doesn’t match our emotional experiences (She thinks my tractor’s sexy, ugh).
The same goes for aesthetics. An American flag conjures up much more emotion in the patriotic individual than another piece of colored cloth. The image means something more. It is a communication of ideas, and it conjures a whole litany of emotions and memories. A swastika can cause repulsion. A rose can fill us with romance. We have learned that certain images mean more than the photons hitting our retina.
Neither language, music, or aesthetics is rational. It’s all emotional.