While illocutionary acts relate more to the speaker, perlocutionary acts are centered around the listener. Perlocutionary acts always have a 'perlocutionary effect' which is the effect a speech act has on a listener. This could affect the listener's thoughts, emotions or even their physical actions. An example of this could be if someone uttered the sentence "I'm hungry." The perlocutionary effect on the listener would persuade them to maybe make a sandwich for the speaker. wikipedia 