I filed a bug:
http://bugs.pearsoncomputing.net/show_bug.cgi?id=2657

I can't get KTTSMgr to find any voices on two different installations on 
Stretch or two different installations on openSUSE 42.1. If it works for you, 
please tell me what you're running it on, and if you can, what I might be 
overlooking WRT to setup to make it work.
-- 
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/