Need Help Finding a Book

I once saw someone asking for book recommendations to help with stuttering, and another person suggested a book. I really need to find the name of that book. What I remember from the comment is that the book was about a king who struggled with stuttering and gradually overcame it during a journey or adventure. It’s not The King’s Speech, because according to the person, the king was from the age of knights. Unfortunately, that’s all I can recall from the comment.