Region subtags and orthographic variants (was: Re: registration requests re Portuguese)

[Yury]

On 04/14/2015 11:31 PM, Peter Constable wrote:
> Doug, I understood him to be saying that having region-qualified prefix field values in the records for any of the three Portuguese-related registrations under discussion is not useful.
...

When marking content '...in cases where it is desirable to indicate the 
language used in an information object' [rfc5646], specifically in cases 
where the distinction are made per the orthography standards (e.g., 'pt' 
case), the 'region' element is unnecessary (extraneous) either in 
'prefix' of this list forms or in rfc5646-conforming 'langtags' themselves.

In this specific case, you don't have any 'extlang', so you don't have 
to over-specify in the 'Prefix' field [rfc5646, p.41].

I see two categories of situations in which a 'region' element actually 
is useful, even necessary, one being wide generalisation of content 
(like in the en_US case), another -- to which this registry would hardly 
ever get down to -- marking the dialectal varieties.

-Yury