Last modified: 2009-06-25 14:16:42 UTC
All feed URLs should implement the uselang paraamter. Just as e.g., the content of RecentChanges changes if you add uselang=xyz to the URL, so should the feed content.
The RC feed *does* support the uselang parameter. But because of broken caching, it expresses the functionality in strange ways… See e.g. http://ab.wiktionary.org/w/index.php?title=Special:RecentChanges&feed=rss&uselang=ru – the result will be in Russian (and in Cyrillic), unless somebody visited the page a few seconds before you with a different user language. I have created a new bug for the broken caching – see bug #19391.