Is a deaf player allowed to have an interpreter accompany them to translate for them during tournament play?

[BombingBerend]

Seems like an obvious yes to me, but can’t find any rule for this. I’ve allowed it at prereleases previously and these interpreters know nothing about the game, so seemingly no competitive advantage.
Now he wants to play our League Challenge and since this is a premier event with CP awarded I want to make sure we follow the rules. Closest description I can find in the Tournament Handbook is a chaperone, which is a spectator and rules for spectators would make their job impossible. Would love to know if there is a ruling about this so that I can refer to it if someone is that serious about their points that they protest about the interpreter.

 

[PokePop]

Pokemon is all about acceptance and giving players with issues accommodation as much as possible.
If you feel sure that the translator is not coaching, sure, it is a reasonable accommodation.