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.