How to create multi-lingual newsletters
The multi-lingual newsletters are not supported by default. If you use the localization macros it resolves them according the actual culture of CMSDesk.
You could create two newsletters - one for each language.
Then you could add this to the page load method of newsletter webpart:
if (CMS.GlobalHelper.CultureHelper.GetPreferredCulture() == "nn-no")
mNewsletterName = "NewsLetter_NO";
else
mNewsletterName = "NewsLetter_EN";
Where
mNewsletterName is the name of the newsletter used in saving the new subscribers.
See also: Applies to: Kentico CMS 3.x