There are countless ways to communicate without using words or speech. You could use mere expressions to give vague hints. It's more challenging if the reader can't see her exact thoughts. Some players can't help letting their PCs comprehend what she means if they understand it themselves. But if the other players are unsure exactly what she means, then they can't accidentally break the fourth wall by letting their characters know things that they as players know.

Failure of communication, while it can only mean invasion (subtle Star Wars reference), can build an interesting interaction chain. Especially if the others misinterpret her intent.