With JAWS 18.0.2738 the Sort attribute is announced as expected in Internet explorer but not Firefox. When navigating to the city column header JAWS does not announce Sorted Ascending. Note this is for the example without the button. When there is a button the aria-sort is announced as expected in Firefox. NVDA The ARIA-Sort attribute is announced as expected in Internet explorer and Firefox.
VoiceOver on iOS 10.3 does not announce the ARIA sort attribute.