True Tongue

The True Tongue is the language of the Children of the Forest.

In the books
The "True Tongue" is the language of the Children of the Forest. The name the Children call themselves in the True Tongue means "Those Who Sing The Song of the Earth".

When Bran Stark stays with the surviving Children at the Cave of the Three-Eyed Raven, he overhears them speaking the True Tongue. Leaf knows how to speak to them in the Common Tongue, but some of the other Children can only speak the True Tongue.

Absolutely no words or even proper names from the True Tongue have been given in the novels.