Thuban is implemented with internationalization support. So far Thuban is translated by volunteers to the following languages (apart from its main language: English):
French
German
Italian
Russian
Spanish
To use internationalization under POSIX systems (like GNU/Linux) you have to set the environment variable LC_ALL accordingly (e.g. LC_ALL=fr_FR for the french language support). Please check your systems documentation for details and supported settings. Specifiying LC_ALL on the command line while launching thuban allows appication specific language settings.
MS Windows users have to specify the language to be used via the control bar (which effects all applications).