Silent Steps - Ira Robinson

Tragic devastation drove them underground. Abject desperation brought them back out again.
Their world had changed.  Alien creatures greeted them with misery in tow and enslavement in mind.
Into this world a girl was born.  Made mute by a mistake of birth, Aylen's ability to communicate with others of her kind was absolute. But natural things - animals, trees, the softly creeping things in the night - were open to her, and had many things to teach her...

... including how to save her world from those beings that held her people in thrall. Aylen's first silent steps are just the beginning...