I just wondered, if national language support will be added to
   NetBSD.

The basic support for it is being worked on, but except for the ctype
changes (e.g. calling setlocale()), no programs have been modified to
use it.  This involves several things; primarily converting programs
to actually *use* the locale information for, e.g., the decimal point
character, and converting most everything to use message catalogs.
Also, someone has to actually translate the message catalogs into other
languages.