music has always been tsukishima and yamaguchi's love language. they were too shy to express how much love they truly felt for each other out loud. so music was the medium. they shared songs with each other that they felt matched the emotion they wanted to express. and they were both happy with that.

yamaguchi developed an illness that put him in the hospital. the illness was undiagnosed. all they knew was that it made him weak, and his body wasn't able to function properly. 

speaking was extremely difficult for yamaguchi in his weak state. music became even more important to his communication with tsukishima. he and tsukki would share earbuds and take turns selecting songs to listen to together

there were times that the couple would feel upset that their communication was now limited to music, but most of the time they were happy to be able to communicate in such a deep, thoughtful, meaningful way. 

they loved each other. both of them knew this, and that was all that was important to them.