You must be able to talk.
Wands function by using the Spell Trigger method of item activitation. And Spell Trigger says in its description:
Spell trigger activation is similar to spell completion, but it’s even simpler. No gestures or spell finishing is needed, just a special knowledge of spellcasting that an appropriate character would know, and a single word that must be spoken. Anyone with a spell on his or her spell list knows how to use a spell trigger item that stores that spell. (This is the case even for a character who can’t actually cast spells, such as a 3rd-level paladin.) The user must still determine what spell is stored in the item before she can activate it. Activating a spell trigger item is a standard action and does not provoke attacks of opportunity.
If you can't talk, you're not going to be able to speak that single word, so you won't be able to activate the Wand.