We've never had any problems sticking to ISO639-2 codes (in cases there
isn't a shorter ISO639-1 code available).  I'm interested in what sort of
regional languages you might be dealing with where there are significant
gaps in that standard?

You might also look at ISO 639-3, which is quite comprehensive but also
introduces a fair chunk of complexity:

Craig Franklin

On 2 June 2016 at 08:59, 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 which
> were last updated in 2007. LOC also maintains ISO639-2
> 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.
> Thanks!
> -- greg