Performative verbs are verbs carried out simply by means of uttering them aloud. When a judge sentences someone to jail time, for example, the action is completed when he or she says, "I hereby sentence you to five years in prison," or the like. Compare this with the sentence, "I run every day," in which the verb "run" merely represents the action of moving quickly.
We order the defendant to pay damages in the amount of $20,000.
I move for a mistrial.
I do. (wedding vow)
One can identify a performative verb by using the "Hereby" Test such as the:
I hereby confer upon you the rank of Second Lieutenant.
I hereby promise to buy you some ice cream.