When you speak, the universe listens. That is, if you've been taught the right language. As an infant. By your family. Not excluded by them. Because no one else will teach you, certainly not the woman you love. Not even if knowing the language, being taught it, would explain your world, keep you sane, or make curing someone you love seem possible.
And Wendy Daily, a beautiful linguist:
When you have a secret, you keep it. There is not much else to say. In fact, the best secrets are so secret no one knows they are even being kept. Keeping the secret is the only thing that matters, keeping it from strangers, friends, and family if need be, certainly from husbands, if it has to be that way, and it does. No matter what or who or how dire the sacrifice, do not speak it. Do not speak of it.
They must survive each other and the plot to destroy them to defend a loved one from a deadly, poisonous transformation.