GTK+ 1.2 supports most European and Asian languages.
GDK contains an API for loading fontsets and rendering
multibyte strings, though this book does not cover it.
The stock GTK+ widgets that handle text use this API
and will deal with multibyte strings correctly. GTK+
also supports input methods for Asian languages. GTK+
1.2 does not support
right-to-left scripts, or scripts that require complex
ligatures and unusual line breaks. However, support for
these languages is a high priority for GTK+ 1.4. For
details on future plans, Owen Taylor's white paper at
an excellent resource.
Both GTK+ and Gnome use the
gettext message catalog system to translate
user-visible strings, so any string the toolkit knows
how to render can be translated into foreign languages.
the section called
Internationalization in the chapter called Gnome
Application Basics covers this topic.