I'm reporting this for a blind person, who sent an e-mail to firstname.lastname@example.org. He uses Voice-Over on his Mac as his screenreader software (using Safari as browser).
He reports, that after loading a large article, Voice-Over and/or Safari use a lot of CPU power and the PC hangs for seconds and even after this, voice-over reacts very slowly. He reports that this problem occurs since 22nd of November, the day the changes of T20338 became live on de.wikipedia.
With the introduction of WAI-ARIA groups, the whole article is one group for Voice-Over. Before, each paragraph was an own group. Most likely this screenreader software can't handle such large groups like a very long wikipedia article.
For the moment, he can't really use wikipedia.
OS: Mac OS X 10.7