This allows you to select whether or not you would like to have Text to Speech enabled and the engine you would like to use.  If you would like TTS enabled, you should try to use the Direct SS engine as it is more efficient.  Some systems may have problems with this engine so if it doesn’t work, you can try the TTS Class engine instead.  If you have SAPI 5 installed, you may also use the SAPI 5 selection.