Psy: Alien Castaways 3 by Cara Bristol

When alien mind reader Psy meets his human genmate, Cassie Steward, he discovers she has been robbed of the ability to speak. He believes he can use his psychic ability to help her speak. But when he unlocks Cassie’s mind, he discovers something far more sinister than a congenital defect is keeping her silent. Will liberating her truly free her or will it destroy their bond?