Current P3 support ja, en and zh only. If you want to add your locale to P3, add locale directory at P3_Settings/ComponentWord/ and translate xml files.
Mac OS X user can localize also. Right click Peraperaprv.app icon and Open Package.... PeraPeraPrv.app/Contents/Resources/Java/P3_Settings/ComponentWord/ is locale file directory.
If you want use your localize strings in official P3:PeraPeraPrv, Please add locale column and fill translated words on following spreadsheet. Developer lynmock will publish with new locale files.