CLIENT SET LANG

Usage: CLIENT <class> SET LANG <language code>

This will set the default language used by all memembers of the specified client class. To use the server default just enter the command with no language specified and the default language will be set.

Example:
/as client Z-default set lang en /as client Z-default set lang

You can find out more information about multiple language support by going to the LANGUAGE help pages.