Honestly i don't get to say in this but from the looks of it she doesn't even try to act out even the simplest expressions or words, much less a conversation for example maybe a nod or shaking the head, wanting to sleep or eat or when she's feeling sick, I know she doesn't understands anything but you can still sometimes guess what the other person might be saying, she had done it couple times and I guess she tried to act out the expression when she just got to that world and it didn't work out, but that was towards strangers, but what about a guy who saves her life, lets her tags along with him gave her food and even concern about her wellbeing? She doesn't even let a voice out to the point the guy even assumes that she's not being able to talk.
All and all thats what makes this interesting tbh I'm definitely curious on how their relationship will work out
Honestly the way it is now is really frustrating to read with all the misunderstanding and the lack of communication, but I believe thing will get better, cuz the plot is something that I've never read before and am definitely intrigued on whats coming