In a Terminal window, set the LANG environment variable to the desired language. For example, to set the locale to Japanese, you can type:
LANG=Japanese_locale
where Japanese_locale sets the value of the LANG environment variable for the Japanese character set. Refer to your specific platform to determine the value for Japanese_locale.
In the same window, call Text Editor (dtpad) under the desired language by typing:
/usr/dt/bin/dtpad &
To start Text Editor with the Japanese language directly, type:
/usr/dt/bin/dtpad -xnllanguage Japanese_locale
You can now enter Japanese characters if the locale-specific files have been installed. You can also use the Text Editor session to edit a previously created Japanese file.
See To Specify Fonts from the Command Line for an example of specifying a font set.