Keep in mind that Unity has two TTS engines available, RealSpeak and TTS3000. RealSpeak costs more and sounds better. If you have TTS3000 you might want to by an upgrade with RealSpeak.
Markus is correct from a supported standpoint and if you have RealSpeak you only have the one 'female' voice. If you have TTS3000 it is possible to change the speakers voice however. I caution you that nothing but the default has been tested and none of these are supported. i.e. back things up before you start making adjustments.
Go to HKLM\Software\Active Voice\TTS\1.0\Initialization\Speakers
There youll see keys for each of the languages (ENU is US English which is the one Im guessing you want to adjust). This change does require you restart Unity.
These are the paths to get to each CCX logs through CLI. They may be helpful if you are having issues accessing RTMT or downloading logs through it.
If you want to download them you have to prefix "file get " and you can add one of the options (re...