- From: Asmus Freytag <asmusf@ix.netcom.com>
- Date: Tue, 13 Mar 2007 13:07:59 -0700
- To: Richard Ishida <ishida@w3.org>
- CC: www-international@w3.org
On 3/13/2007 12:12 PM, Richard Ishida wrote: > This is an attempt to summarise and move forward some ideas in a thread on www-international@w3.org by Christophe Strobbe, Martin Duerst, Bjoern Hoermann and Tex Texin. > http://lists.w3.org/Archives/Public/www-international/2005JulSep/0163.html > You have the classic problem of content tagging here. When applying tagging to content you can have these cases: 1) you have content that has not been classified 2) you have content for which classification has failed 3) you have content that is known to not fit any of the classifications 4) you have content to which the classification cannot apply 5) you have content that fits multiple classifications 6) you have content for which the classification depends on context 7) you have content that has been incorrectly classified 8) you have content that has possibly be correctly classified 9) you have content that has been correctly classified in the case of tagging natural language content, the label "zxx" is clearly the correct one for case 4. When there is no linguistic content, the classification cannot apply. "und" seems a fine label when you want to convey that tagging has not happened (case 1 or 2 - the distinction between these is not necessarily of sufficient interest to carry it forward). But so would the empty tag if it had been allowed. Case 3 could be handled with any form or label that says "no tag assigned yet", but failing that, if available, a private tag might be useful. A single string like "OK" is an example that could fit category 5. Case 6 is not something that I would expect for language tagging, but it's a concept that shows up when assigning script tags to runs of text. Case 7 is something that the tagging systems rarely handle, but for archiving and scholarly purposes it is conceivable that there is a need to express the concept that the content tagging implies a re-tagging of existing content because of errors or disagreement with the previously assigned tags. Case 8 is where you've successfully classified, but there's a margin of error (perhaps machine classification). Finally, 9 is when you have assigned any of the existing tags with confidence. (And case 10 could be where this assignment has been reviewed and verified, but that's again something that belongs more in the scholarly realm). With any tagging system you need to decide which of the distinctions here you need to convey. The usual problem is that tagging systems get designed with 99% of the attention focused on case 9, and there on issues such as how fine grained the tags need to be and what features of the content to base the classification on. Just some thoughts, A./ > > You should always use the lang and/or xml:lang attributes in HTML or XHTML to identify the human language of the content so that applications such as voice browsers, style sheets, and the like can process that text. (See Declaring Language in XHTML and HTML[1] for the details.) > > You can override that language setting for a part of the document that is in a different language, eg. some French quotation in an English document, by using the same attribute(s) around the relevant bit of text. > > Suppose you have some text that is not in any language, such as type samples, part numbers, perhaps program code. How would you say that this was no language in particular? > > There are a number of possible approaches: > > 1. A few years ago we introduced into the XML spec the idea that xml:lang=”" conveys that ‘there is no language information available’. (See 2.12 Language Identification[2]) > > 2. An alternative is to use the value ‘und’, for ‘undetermined’. > > 3. In the IANA Subtag Registry[3] there is another tag, ‘zxx’, that means ‘No linguistic content’. Perhaps this is a better choice. It has my vote at the moment. > > > > [xml:lang=""] > Is ‘no language information available’ suitable to express ‘this is not a language’? My feeling is not. > > If it were appropriate, there are some other questions to be answered here. With HTML an empty string value for the lang or xml:lang attribute produces a validation error. > > It seems to me that the validator should not produce an error for xml:lang=”". It needs to be fixed. > > I’m not clear whether the HTML DTD supports an empty string value for lang. If so, the presumably the validator needs to be fixed. If not, then this is not a viable option, since you’d really want both lang and xml:lang to have the same values. > > [und] > Would the description ‘undetermined’ fit this case, given that it is not a language at all? Again, it doesn’t seem right to me, since ‘undetermined’ seems to suggest that it is a language of some sort, but we’re not sure which. > > [zxx] > This seems to be the right choice for me. It would produce no validation issues. The only issue is perhaps that it’s not terrible memorable. > > Thoughts? > > RI > > > [1] http://www.w3.org/International/tutorials/language-decl/ > > [2] http://www.w3.org/TR/REC-xml/#sec-lang-tag > > [3] http://www.iana.org/assignments/language-subtag-registry > > ============ > Richard Ishida > Internationalization Lead > W3C (World Wide Web Consortium) > > http://www.w3.org/People/Ishida/ > http://www.w3.org/International/ > http://people.w3.org/rishida/blog/ > http://www.flickr.com/photos/ishida/ > > >
Received on Tuesday, 13 March 2007 20:08:16 UTC