Yes, adopt the RFC1766 syntax (which specifies "-" as the separator, as in
en-US). Since RFC1766 also specifies the registration procedure for new
language tags, it would be better to point at the registry rather than
including a list that will go out of date.
Regards,
Owen Rees <rtor@ansa.co.uk>
Information about ANSA is at <URL:http://www.ansa.co.uk/>.