According to this bug: 53842 aria-sort support was added to Webkit quite a while ago. However it does not seem to me as if this is actually working in Mountain Lion VoiceOver + Safari 6. Did it break, or was support never added in the Operating System ?
<rdar://problem/14830320>
This issue is in response to trying to add aria-sort support to Wikipedia. https://gerrit.wikimedia.org/r/#/c/80872/
Where are you applying this? To just any old table? or column header?
To a columnheader in a thead. I also tested this example: http://www.oaa-accessibility.org/examplep/grid2/ which also doesn't seem to work. You DO get ascending/descending feedback in that example, but that is from the live-region, that is being updated. The columnheader itself does not seem to present this information to the user.
Still no support for aria-sort it seems
(In reply to comment #5) > Still no support for aria-sort it seems Safari 9 Seed 1, on 10.10.4
Looks like WebKit exposes all the info correctly. VoiceOver just needs to use it. Technically this is no longer a webkit bug since a fix will not happen in the webkit code base. This radar is tracking the VoiceOver work <rdar://problem/14830320>