Provide a starter init.el file about speechd-el

[mz-pdm]

Examples or a working init.el file, which can be very useful for beginners,

What kind of example would you like to have? There is nothing special needed to be in the init file to start using speechd-el. As for customization, good starting points are `M-x customize-group RET speechd-el RET' and "Configuration" section of speechd-el manual. AFAIK there are no better resources. If you struggle with something particular, suggestions what could be added to the manual to make it clearer are welcome.

Speechd-el does not honor speech-dispatcher settings set in the user configuration speech-dispatcher directory in neither emacs.conf nor in speechd.conf files,

Those configuration files are not processed by the clients but by Speech Dispatcher itself. speechd-el identifies itself to Speech Dispatcher as client "Emacs" and as the user equal to your system user name. If the matching doesn't work in your configuration files, you can ask on the Speech Dispatcher mailing list what can be wrong with your configuration.

I don't think speechd-el overrides the default parameters by default. But you can customize speechd-voices variable, see speechd-el manual. If you specify some settings for `nil' (default) voice then they should take precedence over default and configured Speech Dispatcher settings.

[mz-pdm]

Closing this as it is unclear what exactly is requested.
BTW, there are several speechd-el setup tips at https://diesenbacher.net/blog/entries/Updated-speechd-el-config.html (courtesy to Otto Diesenbacher-Reinmüller).