Silence and Prepare-To-Die Skills.

[Tayl]

Prepare to die skills state that it is a character verbal to activate the skills. Does this mean that they can not be used while silenced?

See;
The Slay applies to only one landed blow, and will remain active until the blow is landed or ten minutes pass. When first activating the skill, the character must say “Prepare to die!” Once declared, this skill must be called with every swing (or thrown weapon/arrow/bolt, including when wielding two weapons or swapping out weapons) or it is considered expended. Using other skills that do not involve swinging your weapon (such as casting a spell) do not interrupt this skill
arb p.67

Emphasis on "The character must say "Prepare to die!"

 

[kalindra]

The phrase "Prepare to die!" is an out-of-game call, so you may use PTD skills while Silenced.

Under the Silence description, ARB page 123:
"The player must still call out the damage points his or her weapons inflict if combat ensues while the spell is in effect, as well as any out-of-game phrases such as “Reflect Magic,” “Parry” or “Prepare to Die.”