What is the Legal issues in using Hazel from Microsoft can she be used on Radio ?

We checked this out a few months ago, and it appears that she is indeed free to use, in terms of the results produced. If you want more details though, you need to look on the Microsoft website, as they own the copyright. As a matter of course, you should check that your particular use is covered - don't rely absolutely on anything I've said! BTW It's only the 'free' voices that this applies to; if you want to use any of the others, you need a commercial licence.