Retired 639-3 codes

Doug Ewell doug at
Mon Dec 14 06:11:27 CET 2009

Michael(tm) Smith <mike at w3 dot org> wrote:

>> aex      Amerax eng
>> [...]
>> yib      Yinglish       eng
> Well, those are certainly interesting. I wonder how many other cases 
> that list might have in which the preferred value cited is itself an 
> invalid tag.

'eng' is a perfectly valid code element in ISO 639-3.  It is not a valid 
subtag in BCP 47, but John gave us a list of ISO 639-3 code elements, 
not BCP 47 subtags.


> Interesting. What set of data does that tool use as its source? How 
> does it distinguish "eng-840" from just being a completely invalid 
> code, and know to cite "en" as a replacement for "eng" or "eng-840"?

It would have to use its own set of supplementary data in addition to 
the Registry.  My application uses supplementary data to do something 
different: when the user selects language subtag 'en', for example, 
there is a "More information" link that will pull up the ISO 639-3 Web 
page for 'eng'.

> Was "eng" ever valid? Is it in a different class of 
> retirement/deprecation than the "eml" case?

Again, be careful not to confuse ISO 639-3 code elements with BCP 47 
subtags.  'eng' is and has always been a valid ISO 639-3 code element. 
It is not and never will be a valid BCP 47 subtag, because 'en' --  
derived from the ISO 639-1 two-letter code element -- is used instead 
(for reasons that would be both very difficult and very ill-advised to 
try to change).  There is no retirement or deprecation involved here.

Doug Ewell  |  Thornton, Colorado, USA  |
RFC 5645, 4645, UTN #14  |  ietf-languages @ ­ 

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