Code Changes (CC) in ISO 15924

Addison Phillips [wM] aphillips at
Mon Feb 7 23:11:51 CET 2005

Let me add two things.

First, language tags registered under RFC 3066 that happen to use subtags borrowed from ISO 15924 will remain valid and stable in perpetuity with the meaning given in the registration even if the ISO 15924 MA were to take leave of its senses and do unstable things. That is, "zh-Hant" *means* Chinese written in the Traditional Chinese script regardless of what ISO 15924 may happen to say about the code 'Hant' in the future.

Second, draft-langtags (3066bis) and its registry would accomplish the same result in exactly the same manner, even though instability is not anticipated as a problem for this standard.


Addison P. Phillips
Director, Globalization Architecture

Chair, W3C Internationalization Core Working Group

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: 2005年2月7日 13:41
> To: ietf-languages at
> Cc: Michael Everson
> Subject: Re: Code Changes (CC) in ISO 15924
> On January 28, John Clews <scripts20 at uk2 dot net> wrote:
> > I did however, get a very helpful reply in detail from Doug Ewell,
> > sent privately rather than on the list.
> >
> > With Doug's permission, I will send a copy of his reply to the list,
> > as it thoroughly described the situation that I had originally asked
> > the reviewer and original developer of ISO 15924.
> >
> > Is that OK, Doug? Feel free to send your reply to me to the list if
> > this is as easy as giving me permission to copy your text to the list.
> I've been asked not to perpetuate ISO 15924 discussions on the 
> ietf-languages
> list.
> However, I feel John's question deserves a SINGLE, FINAL on-list 
> answer, for
> the following reasons:
> 1.  John asked for it on-list.
> 2.  Language tagging with script information, implemented with ISO 15924
> script codes, is a key topic on this list at present.
> 3.  The answer shows that ISO 15924 does not suffer from the 
> alluded stability
> problem, which I think is important for the list to know.
> John had asked whether changes to ISO 15924 after the publication date,
> indicated on the Notice of Changes page, were comparable to ISO 
> 3166's reuse
> of the code element CS, which caused major confusion and 
> stability problems.
> My response was that,
> * first, no ISO 15924 codes have been reused, which was the real 
> problem with
> CS (not merely the fact that a code was changed);
> * second, that only one alpha-4 code -- Mand -- has been changed 
> (not eight as
> it initially appeared);
> * and third, the change appears to be a matter of correcting a 
> typographical
> error in the original publication (not a true code change).
> I feel confident in the stability of ISO 15924 codes, both for language
> tagging and for other purposes, and I feel confident that the ISO 
> 15924/RA and
> its Registrar share this list's concern about stability.
> Please direct ALL further questions about ISO 15924 to the Unicode mailing
> list (unicode at unless they are directly related to 
> language tags.
> -Doug Ewell
>  Fullerton, California
> _______________________________________________
> Ietf-languages mailing list
> Ietf-languages at

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