The idnlang.conf file defines aliases of language names.
It is located on /usr/local/etc/idnlang.conf and always loaded
automatically as idn2.conf and .idn2rc.
The aliases in this file can be used just as the real names.
As described in idn2.conf(5), idnkit has a configuration
parameter named current language.
Unless the current language is specified by the language entry in
the idnkit configuration file, the idnkit library guesses the current
language from locale information at run time.
The idnkit library assumes the language name is an ISO639 language code
(e.g. en), but the language name taken from locale information
may not be (e.g. English).
Using idnlang.conf, you can avoid the trouble.
The alias file is a simple text file, consisting of lines
(other than comment lines, which begin with #, and empty lines)
of the form:
where alias-name is an alias name to be defined, and real-name
is its real name.