ID3 renamer - Preferences - Program language

Preferences - Program language window:

Preferences - Program language

Translation file

Here you can select file with translation. Languages you can find at www.id3renamer.com .
Bottom you can see some information from translator - language, author, revision, ...

Note: Language files must be stored in the subdirectory 'langs' in directory with application (i.e. C:\Program Files\ID3 renamer\langs\).