Add Likely Subtags first step

Phillips, Addison addison at
Sat Jan 24 18:46:04 CET 2015

Hi Mark,

+1 to deprecating remaining grandfathered codes.

Actually, use of a single extended language range was a conscious decision. Having a list of alternatives would have made the canonicalization algorithm more complex (among other things, it would mean defining the LPL syntax and how to canonically match it). In the case of a tag or subtag with multiple replacements, some human agency needs to choose the best alternative.

Note that ‘i-default’ was and is a special case. It is apparently not the same as ‘und’, although the meaning is very close. The RFC says:

   7.  The grandfathered tag "i-default" (Default Language) was
       originally registered according to [RFC1766<>] to meet the needs of
       [RFC2277<>].  It is not used to indicate a specific language, but
       rather to identify the condition or content used where the
       language preferences of the user cannot be established…

And RFC 2277 says:

   Messages in Default Language MUST be understandable by an English-
   speaking person, since English is the language which, worldwide, the
   greatest number of people will be able to get adequate help in
   interpreting when working with computers.

   Note that negotiating English is NOT the same as Default Language;
   Default Language is an emergency measure in otherwise unmanageable

   In many cases, using only English text is reasonable; in some cases,
   the English text may be augumented by text in other languages.

I recall John Cowan pointing out this out during the 3066bis discussions, which is why i-default was consciously not deprecated at that time.


From: Ietf-languages [mailto:ietf-languages-bounces at] On Behalf Of Mark Davis ??
Sent: Saturday, January 24, 2015 9:22 AM
To: Doug Ewell
Cc: ietf-languages
Subject: Re: Add Likely Subtags first step

I would be very much in favor of deprecating all of the grandfathered codes, and if supplying preferred values.

BCP47 says the following. Unfortunately, we used the "extended language range" instead of a language priority list, which would have made it easy. So that means we have to list the alternatives in a comment instead of having them be machine readable:

The field-body of the 'Preferred-Value' for grandfathered and

redundant tags is an "extended language range" [RFC4647<>] and

might consist of more than one subtag.

​Of these grandfathered codes, then, the following have not been deprecated. I suggest that we deprecate each of them, and supply alternatives where possible (in the description, and for zh-min). The preferred value for en-GB-oed could use a new variant tag ("oxford"). The preferred value for i-default could be "und".







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