Maria's answer seems to work for most pages, *except* for root pages in a site, where the option 'Delete Language' is greyed out.
Anyone have any further ideas?
You can do a little workaround. If you temporarly change the startpage in web.config or Episerver manager to another page then you should be able to delete the language. Then you just change it back again.
Hope that will do the trick
Yes, this workaround solved the problem, thanks very much for your reply.
This still might be a problem for regular users as they don't have access to the web.config.