Language subtag registration for acor1990 (ammended from ao1990)

[Michael Everson]

The reason I brought António into this was that I know that the "Accord" is really very controversial in Portugual, and some users will simply not accept it. We have seen the same thing with German. (Indeed my update of the 1870 Alice was published in pre-Schlechtschreibung orthography). 

If it makes good sense to be able to tag the "new" orthography, it makes the same good sense to be able to tag the previous non-Brazilianized orthography.

The way that we have done this before is to have a subtag defined by a reference work, to a particular specification of the orthography. Not to a governmental decree, for instance, but to a (mostly at least) complete instantiation of the orthography in question.  I don't know that we need to be able to tag every revision of the orthography, but the pre- and post-"Accord" division is a bit of a watershed. 

Can António and João point to such authoritative works for each orthography? My own library has "Gramática Portuguesa" by José Maria Relvas, 2005, which appears to be in pre-"Accord" orthography. But it may not be comprehensive. 

Michael Everson * http://www.evertype.com/