The role of the Speaker throughout The Giver is to enforce rules and issue announcements throughout the community. The reader is first introduced to the Speaker in Chapter 1, as it issues a command that all citizens in the community immediately go into the nearest building and stay there until further notice. The Speaker then explains to the community that the pilot flying the jet plane has been "released." Throughout the novel, the Speaker goes on to issue reminders to the citizens to follow proper procedures and chastises individuals who have broken community rules. Jonas recalls a time when the Speaker announced that snacks must be consumed in the designated eating area after he innocently took an apple from the recreation area.

This anonymous, faceless authority is rather unsettling and serves a strategic purpose in Jonas's utopian society. The Speaker somehow addresses every offense committed throughout the community, which is ominous and demonstrates the extensive control the Committee of Elders has over the citizens. Interestingly, the only person who has the ability to turn off the Speaker is the Giver in his Annex.

The speaker’s job in Jonas’s community is a combination of enforcement and announcements.  For example, when the jet flies overhead, the speaker tells everyone to drop their bicycles and go inside, presumably to protect them from the possible danger.  However, the speaker also is used for public shaming.  When Jonas takes an apple home to inspect it for changing, the speaker makes an announcement that reminds him of the rule against hoarding food. 

The only thing that happened was the announcement later that evening over the speaker, the announcement that had singled him out without using his name, that had caused both of his parents to glance meaningfully at his desk where the apple still lay. (Ch. 3) 

The announcement is effective, even though it does not name him.  All Jonas’s parents have to do is look at him.  They know that the announcement refers to him.  By making the announcement, the speaker reminds everyone in the community that they are always under surveillance.  Resistance is futile.  The speaker keeps them in line.  When Jonas starts his training, he is surprised that The Giver can flip the switch on the speaker.  No one else can.