I recommend reading https://tools.ietf.org/html/rfc5646 which seems to do
what you need.
...let us be heard from red core to black sky
On Thu, Jun 2, 2016 at 10:59 AM, Greg Lindahl <[log in to unmask]> wrote:
> Some of the Internet Archive's library partners are asking us about
> language metadata for regional languages that don't have standard
> codes. Is there a standard way of dealing with this situation?
> Overall we use MARC codes https://www.loc.gov/marc/languages/ which
> were last updated in 2007. LOC also maintains ISO639-2
> https://www.loc.gov/standards/iso639-2/php/code_list.php last updated
> in 2014.
> The languages in question are regional languages which are currently
> lumped together in both standards. With the recent rise in interest
> and funding for regional languages, it's no surprise that some
> catalogers want to split these languages out into separate codes.
> -- greg