Gerard Meijssen <gerard.meijssen(a)gmail.com> writes:
Hoi,
There are standards that define British English et al.
It makes part of the ISO codes. We do not have to invent
something like "ISO 639-3eng".
Indeed.
There is a nice tool maintained by W3C corroborator Richard
Ishida to look up current IANA defined language tags, and their
constituents (subtags) at:
http://rishida.net/utils/subtags/
Greetings -- Purodha