ISO 639 and RFC 3066bis

Addison Phillips [wM] aphillips at
Tue Jul 27 04:04:13 CEST 2004

To be a bit more direct: RFC 3066 follows ISO 639 and ISO 3166's assignments of codes. Therefore instability (and potentially, as with 'CS', ambiguity) of the assignments in the underlying standards affects the stability of language tags over time as well. This is one of the primary design goals of RFC 3066bis: to prevent content labeled with a particular language tag from becoming obsolete or having its meaning change.

The addition of a stable, concrete registry helps prevent or delay problems with content tagging too, at least over the medium term, since reconstructing the list of valid codes from various discrete sources is no longer necessary. The design of the draft should prevent this from becoming an issue again. And RFC 3066bis maintains strict and permanent backward compatibility with existing language tags (including those that have become inadvertently invalid). 


Addison P. Phillips
Director, Globalization Architecture
webMethods | Delivering Global Business Visibility
Chair, W3C Internationalization (I18N) Working Group
Chair, W3C-I18N-WG, Web Services Task Force

Internationalization is an architecture. 
It is not a feature.

> -----Original Message-----
> From: ietf-languages-bounces at
> [mailto:ietf-languages-bounces at]On Behalf Of Doug Ewell
> Sent: 2004年7月24日 13:33
> To: ietf-languages at
> Cc: Harald Tveit Alvestrand; John Cowan
> Subject: Re: ISO 639 and RFC 3066bis
> Harald Tveit Alvestrand <harald at alvestrand dot no> wrote:
> >> Correct.  But we are already treating some of them as valid in RFC
> >> 3066 (the transitionally reserved ones) and I'm arguing for treating
> >> some of the exceptionally reserved ones (the oddball territories) as
> >> valid too.
> >
> > which reserved codes are we treating as valid in RFC 3066?
> The way I read RFC 3066, none of them:
> "All 2-letter subtags are interpreted as ISO 3166 alpha-2 country codes
> from [ISO 3166], or subsequently assigned by the ISO 3166 maintenance
> agency or governing standardization bodies, denoting the area to which
> this language variant relates."
> Strictly speaking, if a country code is no longer part of ISO 3166 (like
> TP or YU or ZR) then it would appear to be no longer valid under RFC
> 3066.  However, most implementations would probably consider such
> withdrawn codes to be valid, not because of their current
> "transitionally reserved" status but because they were formerly ISO 3166
> codes.  (ZR might be considered valid under RFC 1766 only, since it was
> withdrawn from ISO 3166 before RFC 3066 was published.)
> This is one of the things RFC 3066bis seeks to change; loosely speaking,
> withdrawn ISO 3166 (and ISO 639) codes would be explicitly valid, but
> would be considered aliases for the equivalent current ("canonical")
> code.
> So far, nobody has commented publicly about the list of exceptionally
> reserved ISO 3166 code elements that John Cowan proposed.  They are
> listed (as comments) in my prototype registry; search for the name
> "Cowan" to find them.
> -Doug Ewell
>  Fullerton, California
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