For example, a form contains a group of radio buttons that pertain to payment. For the exclusion group as a whole, you need speak text to say “Select the method of payment”. For each of the buttons, you need a value for “Cash”, “Credit Card,” and “Check”. When the user tabs into the exclusion group and the first radio button, Cash, becomes active, the screen reader says the type of object and then says “Select the method of payment. Cash” and then it says the state (whether it is checked or unchecked).
LiveCycle Designer ES includes options that support screen readers for defining speak text. You can use the Accessibility palette to define custom screen reader text and tool tips. You can also use object names, as specified in the Name option of the Binding tab, and captions. In most cases, the captions for the radio buttons should provide meaningful text for the screen reader.
See also 

To make radio buttons accessible