New versions of Windows often add new text-to-speech voices. Windows Vista added Anna which was retained up to Windows 7. Windows 8 also had new voices, David, Zira and Hazel. Windows 10 features a set of additional voices in Technical Preview. In the current build 9879 of Windows 10, enthusiasts have discovered the following new voices in the US English version : Microsoft Mark Mobile and Microsoft Eva Mobile, and a special test voice designed for Cortana. The older Windows 8 voices are also present. It is possible to unlock the "Eva" voice and check it out if you're interested. Here is how.