Ergänzung

[Gunnar Bittersmann]

alfie,

Deprimierend. Es wäre einfach zu schön gewesen, automatische alle nichtvorhandenen Klassen der entsprechenden Familie zuzuordnen (also de-at, de-ch, de-lu, de-li zu de).

It could well be argued that RFC2616 has made an unfortunate choice in this regard, due to its counter-intuitive behaviour. It's at least plausible that if the server had no British English variant then the best way to respond to a request for en-GB would be to return a generic English variant, and that the user should be expected to take some additional action (such as including "en;q=0" amongst their preferences) if they want to indicate rejection of a generic variant.
(http://ppewww.ph.gla.ac.uk/~flavell/www/lang-neg.html)

Und zu meinem Einwand ebenda:
RFC2616 puts the responsibility on the browser designer to assist the user in understanding the consequences of this rule and to help them in including the generic language in their list if this is their intention (I know of no browser which actually offers this assistance!).

Gunnar