Text to Speech In metro style app

Question

Hey 

Is there any text to speech API available in metro style app's.I used the System.Speech but it doesn't work for metro style apps 

Is there any way i could achieve a text to speech conversion .some 3rd party libraries .And if yes what are they.

Also is there a way to do it without using the internet connection.It wont be preferable for my app ??

Thanks..