Inexplicably and as noted in the bug I filed, KTTSMgr is now working
on my friend's Stretch.

Voices still could not be found either via KTTSMgr or KSayIt in my
own Stretch or either his or my own 42.1. Trying via KSayIt instead
of KTTSMgr in my Stretch could not find any voices either, but instead
of query windows that stay open indefinitely, they only stayed open a
few seconds and then disappeared, resulting in a not configured, would
you like to now window, also from which no voices were ever found.

NAICT, nothing ever starts any Festival process in any of the non-working
installations, while ps -A shows it running in the working one. Nothing
in /etc/init.d/ contains strings estiv or oice.

Trying to run festival in konsole (e.g. Stretch host big41) produced:
$ /usr/bin/festival
"Could not find any of these voices:"
(nitech_us_slt_arctic_hts nitech_us_awb_arctic_hts nitech_us_bdl_arctic_hts nitech_us_clb_arctic_hts nitech_us_jmk_arctic_hts nitech_us_rms_arctic_hts kal_diphone ked_diphone cstr_us_awb_arctic_multisyn cstr_us_jmk_arctic_multisyn)

WARNING
No default voice found in ("/usr/share/festival/voices/")
either no voices unpacked or voice-path is wrong
Scheme interpreter will work, but there is no voice to speak with.
WARNING
Festival Speech Synthesis System 2.4:release December 2014
Copyright (C) University of Edinburgh, 1996-2010. All rights reserved.

clunits: Copyright (C) University of Edinburgh and CMU 1997-2010
clustergen_engine: Copyright (C) Carnegie Mellon University 2005-2014
hts_engine: All rights reserved.
For details type `(festival_warranty)'
festival>    

So, I looked myself, and also couldn't find voices, as I had been able
in openSUSE 13.1/KDE3. I searched with
aptitude, and unlike on openSUSE, found voice packages available untied
to festival. I then installed some, with this result:
# cat /pub/Tmp/out
# dpkg -l | egrep 'fest|oice'
ii  festival                              1:2.4~release-2+b2                amd64        General multi-lingual speech synthesis system
ii  festlex-oald                          1.4.0-4                           all          Festival lexicon from Oxford Advanced Learners' Dictionary
ii  festvox-en1                           1.95-1                            all          mbrola-en1 voice support for festival
ii  festvox-us1                           1.95-1                            all          mbrola-us1 voice support for festival
ii  festvox-us2                           1.95-1                            all          mbrola-us2 voice support for festival
ii  festvox-us3                           1.95-1                            all          mbrola-us3 voice support for festival
ii  mbrola-en1                            19980910-2                        all          British English male voice for Mbrola
ii  mbrola-us1                            0.3-2                             all          American English female voice for Mbrola
ii  mbrola-us2                            0.1-2                             all          American English male voice for Mbrola
ii  mbrola-us3                            0.1-1                             all          American English male voice for Mbrola

Speaking clipboard with KTTSMgr now purports to work, but no sound occurs.

NAICT on friend's machine, the content of /usr/share/festival/voices/english
on Stretch and 42.1 installations are the same, even though Stretch provides
voices via separate packages, while 42.1 offers no festvox or mbrola packages
separately from festival.
-- 
"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/