MS MATEJ under Edge beta

 I like it a lot, especially because it doesn't require IIS for local storage operations when working with local html files. 
My problem is that voice MS Matej (Croatian) is not supported for read aloud. Do you know will or when it be available or do I have to configure something to make it work? 
For example this demo: https://developer.microsoft.com/.../demos/speechsynthesis works on the old edge, but not on new one.