As they learn the language they do in school, teach them another language. Don’t stop there though, choose one that you don’t know either. I feel this would remove some of the gap in language, when we are both struggling with the limitations of our words. I think it’d help remove the ego and allow for some empathy and understanding of what they may be trying to say.
As for the learning, perhaps it would help to be with someone who speaks a language you don’t, and to learn that one. I think it’d be a unique mutual-support way of learning a language on both sides.