john doe [2017-12-26 16:34:53+01] wrote:
The installed system is properly set to language 'a' (desktop manager,
Firefox, Thunderbird, Libreoffice, dictionaries ...).
In addition to language 'a', I want to add support for language 'b' so
the user could choose between language 'a' or 'b'. Doing
'dpkg-reconfigure locales' selecting language 'a' and 'b' is not
enough for Firefox, Thunderbird to be translated into language 'b'..
In console mode I can change the language using 'LANG*'. What should I
do to translate Firefox and Thunderbird to language 'b'?
The Debian package system has language "tasks" which can be installed
like packages. You can search your preferred languages with
apt search task-LANGUAGE
where LANGUAGE is the name of the language (like task-finnish).
Graphical package manager programs can probably browse available tasks
too. I would recommend installing such tasks.
Also, some programs have their language-specific files in a separate
package: the name ends with -l10n- and a two-letter language code.