Kris was not always born mute but sometime through their childhood they lost the ability to speak. They learned sign language and used that to communicate with others. until They came upon the dark world, what will happen next? you'll have to read to find out I don't know how long this will be, this is a personal headcannon of mine that Kris doesn't speak much because they physically can't. And majority of the people in the story know sign language to some extent but not all characters do. Also i see Kris as they/them as they're refered to as they/their/them in the game Another thing this might involve chp 2 so beware for spoilers if you haven't seen or played it.