How do they do that?

I was just wondering how sitepal website makes their 3d models work with text to speech? Are there tools and tutorials out there that can show me a workflow of how this is done.

I would like to create something like this for a project I am wanting to do for my kids in creating an avatar from 3d models I have created that they can use.

Hope this isn't too much to ask, but I have been trying to figure this all out. I know how to create animations. I am more interested in finding out how you get the 3d models to speak.

Thanks,

Chuck