Adding text to link captions to prompt users:
<a href="message.html">Leave us a message</a>
Might be spoken as:
To leave us a message, say "yes" or press 5
The additional text could be added via a style property, using CSS2's generated content mechanism, e.g.
a.confirm:before { content: "To" }
a.confirm:after { content: "say yes or press" counter(key) }
...
<a class="confirm" href="message.html">Leave us a message</a>
It is probably insufficient to use a counter as that doesn't bind the key to the element. Adding a key token to the content property would work, e.g.
a.confirm:after { content: "say yes or press" key }
key would act like a counter in other respects but would also have the effect of assigning a appropriate key to the element selected.