Given the previous attempt on her life, going to guess this "teacher" is another guy who's being ordered/offered (?) to off her. Out of the frying pan and straight into the fire, huh, Ms. "Disciple"?
Can't wait for that "friend" to have a breakdown after learning that she's putting her "master" (and probably herself) in danger.
Going off of everything we’ve seen with this hinted antagonist with the scar, my best guess is: She got pregnant but it came out her mouth instead and that’s why she can’t talk