Speak
In general, speaking is a free action that you can perform even when it isn’t your turn. Speaking more than few sentences is generally beyond the limit of a free action.
Oh... I would so approve of this as a DM, and then watch that player like a hawk, triggering the Teleport just as soon as he said those words, because I'm betting he'd use the phrase without even thinking about it.The concern is that one of my players wants to Contingency Teleport to him saying "Oh my."
Were speaking an immediate action, he could use it in reaction to things he didn't notice before they occurred, such as a Rogue Sneak Attacking or a Rock landing on his head.
He can't really do that with a Free Action.