A Positive Influence

In my role as a mother, despite the mundane tasks, I occasionally have the opportunity to make an impact on the minds of my young children. They know not to eat things off the ground (usually) even though it makes them sad. They know some of their alphabet ("P is for Daddy!"). Last night, as they were playing in the bath ("I'm a pirate mommy! Now I'm not a pirate, I'm a princess!") they learned that while Camille can be Princess Camille Lollipop, Grace can be Princess Grace Cutiepie, and Mommy can be Princess Sarah Sweetpea, Daddies can not be princesses, but must instead be princes. But why do "princess" and "prince" sound so similar?