Sitecore stores Danish translations using the ISO code "da" in the default distributive of Sitecore CMS, Intranet Portal, localization files and Sitecore modules.
To be able to localize parts of the Sitecore Client interface, such as template sections, field names and descriptions, it is recommended to use the "da" language instead of "da-DK" in Sitecore content databases, such as master and web.
If the ISO codes in the core and master databases are different, they may cause issues related to being unable to translate parts of Sitecore Client interface, such as template sections, field names and descriptions.
To add a "da" language to a Sitecore solution that does not yet have Danish language in a content database:
If an existing solution is already utilizing a "da-DK" language, perform the following steps to switch to using "da" language:
UPDATE UnversionedFields SET Language='da' WHERE Language='da-DK'
UPDATE VersionedFields SET Language='da' WHERE Language='da-DK'
UPDATE Page SET ItemLanguage='da' WHERE ItemLanguage='da-DK'
UPDATE PageEvent SET ItemLanguage='da' WHERE ItemLanguage='da-DK'