The form buttons on http://jquerymobile.com/test/docs/buttons/buttons-types.html are read twice by VoiceOver (tested with Safari 5.1 on OS X 10.6.8) – first the visible, "fake" button, then the real button. The same thing happens i iOS (tested in iOS 4.3.5) when you let VoiceOver read the whole page by swiping downwards with two fingers.
It appears that setting aria-hidden="true" (http://www.w3.org/TR/wai-aria/states_and_properties#aria-hidden) for the "ui-btn-text" element prevents this and makes VoiceOver speak only the real button.
Thanks for the tip Roger! We'll try to get this in for RC2.
Fixes #2594 — Button text is no longer read aloud twice (and treated …
…as two separate navigable items) in iOS VoiceOver.