Get more Microsoft text-to-speech voices

Does anyone know how I can get more voices?

You can download some more voices from many free TTS voices (which may not be so good). One of the sources for downloading free Microsoft and LTS TTS voices is Zero2000. You can also purchase very high quality TTS voices for Windows from companies like Ivona, Cepstral or CereProc.

Source Choose Text-to-Speech Voice in Windows 10