Pegasus
Robin McKinley2010

Because of a thousand-year-old alliance between humans and pegasi, Princess Sylviianel is ceremonially bound to Ebon, her own pegasus, on her twelfth birthday. The two species coexist peacefully, despite the language barriers separating them. Humans and pegasi both rely on specially trained Speaker magicians as the only means of real communication.

But it's different for Sylvi and Ebon. They can understand each other. They quickly grow close - so close that their bond becomes a threat to the status quo - and possibly to the future safety of their two nations.