Assuming that with "on screen its text remaines in English" you mean the skin and you are using the Shadow4 skin:
From the website
language page:
NOTE If the skin uses bitmaps to draw the months and days, changing the language of the user interface does not affect the calendar on the desktop. To fully localize the application you can download the Shadow4.r2skin-addon which contains localized versions of the bitmaps for the default skin. Note that the file extension must be ".r2skin-addon". If your browser tries to suggest something else (e.g. ".zip") you need to manually change the extension back to its original form.<br><br>Post edited by: Alf, at: 2007/01/06 15:01