You can copy and paste the characters you need from the oto.ini file of the voicebank you're using. Press the plus button to add it to the list, and you'll be able to use it again later. You can simply build up your own list of common suffixes based on the voicebanks you actually use, since the ones in the default list aren't actually the most common suffixes.
You can copy and paste the characters you need from the oto.ini file of the voicebank you're using. Press the plus button to add it to the list, and you'll be able to use it again later