the glenda jackson production of king lear on broadway did something similar with the Duke of Cornwall, and it was actually the best part of the play, imo. because when Cornwall was speaking to Lear or to the Court, he had a sign language interpreter to speak the actual literal words aloud, but when he was talking to and conspiring with Regan, his wife, they were just signing back and forth with no translation for the audience, and it emphasized the intimacy between the two even as they turn against literally everyone else in the play, which was fantastic.
and the best part of it was, by the second half of the play, you were so used to it, that you didn’t even blink anymore when watching him and listening to the spoken words come from the interpreter - you just watched the actor playing Cornwall and let the words come from the other guy, but the guy kind of fades into the background. it didn’t hurt that the actor for Cornwall was one of the tallest on stage, and had bright red hair - it was easy to watch him, instead of his interpreter.
which is why it was so shocking and so perfect when the interpreter is the one who kills him.
See, they folded the character of the servant who kills Cornwall into the person of this character who had been such a non-entity that you almost forgot he was on stage - until you realize, no, this is another person, and he’s been here, watching all this the whole time, and he finally gets to the breaking point where he can’t stand by and translate anymore, he has to do something to stop the cruelty he’s seeing, and it’s not just a random guy who comes in for the scene and sees them blinding Gloucester, it’s the man whose been by his side for the entire play, the man who was his voice who finally has a line of his own. who finally speaks on his own behalf to say “no.”
and then, of course, he gets killed, but Cornwall dies in the same scene so it’s not like they need to get a new translator or anything. but it was the most fucking brilliant choice i’ve ever seen re: casting in a Shakespearean production, and the rest of the play pales in my memory in comparison.