innovations in RFC3066bis

Peter Constable petercon at
Mon Jan 12 21:35:07 CET 2004

It seems to me that the main innovations in the proposed replacement for
RFC 3066 fall into these categories:

1) incorporation of ISO 15924

2) extensions mechanism

3) syntactic changes

3a) purely formal changes (i.e. non-semantic -- syntax in the formal
language sense): (i) use of "." and "%", (ii) sub-tags that are more
than 8 characters long, (iii) non-initial sub-tags that cannot be of any
length up to 8 characters

3b) syntactic/semantic (actually, I think the term "morphological"
fits): establishment of position classes with particular semantics (i.e.
the subtags making up a complete tag must follow a particular order in
terms of the function associated with a given position within the

4) registration of sub-tags, not complete tags

5) ability to use private-use variant sub-tags without requiring
registration (e.g. "en-CA-xmyideolect" can be used without registration;
in RFC 3066, a tag starting with "x-" would have to be used)

There are other less-major changes, but those don't represent as marked
a change from RFC 3066 as do these.

It might be helpful if we orient discussion around these categories.
Note that the changes in 3a presuppose the changes in 2 and 3b, so it's
probably best to establish consensus on 2 and 3b before spending a lot
of time debating the corresponding aspects of 3a.

Peter Constable
Globalization Infrastructure and Font Technologies
Microsoft Windows Division

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