Speaker
The speaker takes in audio data through connected Copper Wires, and outputs it as sound in the world.
Redstone Interaction
The speaker, when used in conjunction with a Redstone Comparator, can output a redstone signal equivalent to the measured loudness of the audio that it speaks. If the sound does not belong to a voice, and is instead a sound being heard through Sound Listening, the signal is equivalent to the distance to the listener that heard it.