Basic Screen Reader Commands related to Forms

Action JAWS (Windows) NVDA (Windows) Voice Over (OS X)
Next control Tab Tab Tab
Previous control Shift+Tab Shift+Tab Shift+Tab
Re-read current control Insert+Numpad 5 NVDA+Numpad 5 or NVDA+Shift+O Command+Option+Space
More information on control Insert+SHIFT+F1 and Insert+Control+Shift+F1 NVDA+D Control+Option+F4
List of Form Controls Insert+F5 NVDA+F7 Command+Option+U, then left/right arrow to forms
Detailed Keyboard Information JAWS Keyboard Documentation NVDA Documentation Voice Over Guide