Valyrian is the mother tongue of the Mother of Dragons, Daenerys Stormborn.

The Valyrian:

"Zaldrizes buzdari iksos daor." (A dragon is not a slave)

"Ydra ji valyre?" (You speak Valyrian?)

"Nyke Daenerys Jelmazmo hen Targario Lentrot, hen Valyrio Uepo anogar eksan. Valyrio muno engos nuhys issa."(I am Daenerys Stormborn of the House Targaryen, of the blood of Old Valyria. Valyrian is my mother tongue.)

Mhysa is Ghiscari, not Valyrian.

Learn Dothraki here: http://docs.dothraki.org/Dothraki.pdf