It would be interesting if there was a mute character on the show, because not only would the actress have to communicate Ariel’s thoughts and feelings without speaking, but then you also start ticking disability boxes in this case- a speech impairment.
That’s not to say the show should add disabled characters just for the sake of adding them, likewise with LGBT characters, but with Ariel, her disability is actually part of her story and can also act as a communication barrier between Ariel and the JR6. Also if Ariel is allied with the JR6 and she finds out information that the JR6 need to know, such as where Henry is, Ariel can try to tell the JR6 what she knows without the JR6 understanding which can prolong the storyline.