Ernest,

> > > If @hreflang keeps to be just meta informational, 
> hreflang="de, en, fr,
> tr" 
> > > could be ambiguous: A document is available in 4 variants or the
> document 
> > > contains four languages... - not a bad ambiguity at all.
> >
> > as i said at the very beginning, with @hreflang being meta-information
> only,
> > I'd much prefer it to have one value only. i think listing multiple
> values in one
> > attribute is not good XML. it complicates further generic processing
> > (XSL-transformations etc.) by applications not aware of the 
> XHTML syntax.
> 
> I'll have to disagree with both of you here.  Suppose a document were
> available in English, German, and a bilingual version.  It would be useful
> to be able to specify hreflang ="de,en" and have it mean that the resource
> is supposed to be the bilingual document. If the intent is supposed to be
> any of the three possibilities, then we would need something like
> hreflang="de en de,en".  However, as I have stated previously, because
> metainfo attributes like hreflang are most useful for non-negotiating
> protocols such as FTP that do not provide any metainfo, I am strongly
> in favor of making them all single valued.  However, in this case, the
> listing
> of multiple languages IS a single value indicating that all the languages
> occur in the resource, not that versions in each language exist.
> 


I do see your point here, and actually i stated in one of my very first mails cencerning this issue that there were situations in the past when i wished i'd had the possibility to express multiple languages with @hreflang.
still, from an XML point of view, i think the multi value solution would be wrong.
we would repeat the same mistake that was made with SVG's @points. it looks like XML, but it isn't. if distinct values can't be identified by corresponding tags/attributes but need to be extracted by some sort of string manipulation (try something like "get the third point that has an X-value greater than 100" with an SVG-document), then we betray the idea behind XML. 
so i'd say: if multiple values seem so important, we should discuss the possibility of doing something roughly like
<a href=...><hreflang>en</hreflang><hreflang>de</hreflang>multi-language-link</a>
if this turns out to be too clumsy, live with the fact that we can't address the issue of multi-language documents.


regards,
oskar