Speakup-enabling recovery or administrative distributions

[Kyle]

You will need the espeakup package, along with alsa-utils. Generally,
these should be all you need to get Speakup and Espeak working together,
since espeakup should pull in Espeak as a dependency. Once you have
these, you will need to load the speakup and speakup_soft modules, which
you should be able to do in whatever configuration file is responsible
for loading kernel modules at boot time. I can't tell you exactly which
file or files are responsible for this, as it differs between distros.
Then you will need to be sure that the espeakup service runs as the live
image boots. If the init system is based on sysvinit/initscripts, you
will need to link /etc/init.d/espeakup to a link in whatever rcx.d
runlevel directory loads the runlevel services needed by the image. The
runlevel is usually 3, but could also be 2 or 5. If the distro uses
systemd, you will need to create a simlink to
/usr/lib/systemd/system/espeakup.service in
/etc/systemd/system/sound.target.wants. Since many rescue distros are
likely based on Debian, you will probably need the runlevel-based
instructions rather than systemd, but I included both here just in case
the images you mention are either distros in and of themselves, or are
derived from different non-Debian distros that use systemd. Keep in
mind, however, that if your images are derived from Gentoo, they likely
use OpenRC, which although it looks much like sysvinit, it is different,
and I'm not entirely sure how to symlink the script into its appropriate
runlevel. It may be very similar to the way it works in Debian, but I
haven't familiarized myself with OpenRC enough to know if it does indeed
work the same way.

The last bit of trickery will involve being sure that the sound card on
the system that boots the image is not muted. Since you have the
alsa-utils package installed, you should be able to use amixer to do
this. Try including a command like

amixer set Master 70%

in a script that runs during the boot process. This is generally enough
to ensure that the sound card is not muted once Espeakup is started
without causing the sound to blast through the speakers. Each sound card
seems to react differently, so the volume may still be rather low, but
in most cases, the above command will allow the voice to be heard. Hope
this is helpful.
~Kyle
http://kyle.tk/
-- 
"Kyle? ... She calls her cake, Kyle?"
Out of This World, season 2 episode 21 - "The Amazing Evie"