The security settings for the current language prevent you from seeing this item. To continue, select another language from the Language drop-down list on the Versions tab.

I saw a few blog posts on this error but took me a while to figure out what the real solution was.  Here is a description of the error and how to resolve it.

Problem: A user is assigned access to edit content in the Content Editor but when they click on an item to edit they get the following error:

The security settings for the current language prevent you from seeing this item.
To continue, select another language from the Language drop-down list on the Versions tab.

Reason: In the content editor on the Master database there is a folder  at /system/languages
This folder has a new security key called language:read and language:write.  By default this is assigned to sitecore\everyone.  This is fine provided that only local users are accessing the content editor but if you are using ad domain\everyone will be default be denied.

Solution: Click on security and access viewer.  Navigate to /system/languages.  click on assign and assign the {your domain}\everyone access to language:read and language:write.   If you want to do this for a specific language you can open the folder click on the language and set these access properties there.