lang ID for "*" (any language)

Peter Constable petercon at
Wed Jun 13 16:27:52 CEST 2012

Thanks, Doug, for the reminder of that text, which is interesting.

Root, which is totally unqualified--I.e., 'neutral'-is different. In a matching mechanism that seeks the best match against a preference list, a neutral resource might be chosen in the absence of any other matching resource. This could be used to qualify a resource as a positive match for any entry in the preference list if there isn't a stronger match for that entry.

Mark, you mentioned using 'und' for some time. Has that been in private or public contexts? (We're looking at something that would be part of the Windows SDK.) And would you say the use was comparable to "root" (which I think is different)?


Sent from my Windows Phone
From: Doug Ewell
Sent: 6/12/2012 5:15 PM
To: ietf-languages at
Subject: Re: lang ID for "*" (any language)

I tend to agree with Mark that 'und' is the best choice for this.

The passage in Section 4.1 seems to start off otherwise:

"The 'und' (Undetermined) primary language subtag identifies linguistic
content whose language is not determined.  This subtag SHOULD NOT be
used unless a language tag is required and language information is not
available or cannot be determined.  Omitting the language tag (where
permitted) is preferred."

but then goes on to give reasonable use cases:

"The 'und' subtag might be useful for protocols that require a language
tag to be provided or where a primary language subtag is required (such
as in "und-Latn").  The 'und' subtag MAY also be useful when matching
language tags in certain situations."

On the list we've often talked about, for example, "und-Cyrl" to
indicate text in the Cyrillic script. In a case like this, it might not
be that the language cannot be determined, but that it doesn't matter.

I think CLDR uses 'root' for a purpose similar to this.

Doug Ewell | Thornton, Colorado, USA | @DougEwell ­

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