Code:
help taunt
[Skills help] taunt
Syntax: taunt <victim>
Swashbucklers can use their razor-sharp tongues to infuriate bystanders and
cause them to attack in a wild rush. A well-aimed taunt can even cause
someone who is already fighting one person to switch to the taunting
swashbuckler as well, even if they don't understand the swashbuckler's
language! The mocking tone of a well-delivered taunt is a language all its
own. Some spell casters may even lose their concentration when taunted by
experienced swashbucklers.
The help files make it seem like taunt is verbal. If taunt is verbal then I think that deafness should affect a swashies ability to taunt.