This fix is for when your built in Voice search app is not working correctly or you have accidentally disabled it. Home screen>Menu>Manage Apps>Voice Search>Clear data & Force stop.
If the issue is that you have it disabled and the Google Play Store is crashing when you attempt to enable it then do the same thing except, Manage Apps>Google Play Store>Clear data, Force stop & uninstall updates. Restart your phone and go enable Voice Search and you should be good to go.
If the issue is that you have it disabled and the Google Play Store is crashing when you attempt to enable it then do the same thing except, Manage Apps>Google Play Store>Clear data, Force stop & uninstall updates. Restart your phone and go enable Voice Search and you should be good to go.