The subject of this movie is not deaf people and society. That's just the framing device that people tend to focus on a priori because the incredible respect to the subject matter that the studio showed.
The real star of this movie is the way they portray the nature and consequences of bullying, both for the victim and the bully. Often in fiction, we overlook the side of the bully, reducing their character to a simple bad guy to be punished. Here the aftereffects of youthful bullying are beautifully and tragically discussed for both to former bullies and the victims, as they are growing up.
The story that unfolds for Ishida and Nishimiya is a romantic drama about learning to forgive and to love: to forgive and love others as well as themselves.
The plot is deep and covers many touchy subjects, such as depression, self-deprecation, social anxiety and suicidal thoughts, current topics that affect all of us around the globe. The entire narrative is a riveting emotional roller-coaster, with heartfelt, tearful moments and sweet gentle ones.
To add to this, the animation from KyoAni is one of the most cinematic I have seen, in both animated and live-action format. The quality of animation alone would be a great movie, but here it is just icing on top of the cake.