In its normal operating mode, the Echo only speaks when spoken to.
Another great feature of the Amazon Echo is that it can be paired with a bluetooth device to which it will automatically connect when the device is turned on. Using a device such as this plugged in to a dumb amplifier or some active speakers can turn the innocent and demure Echo in to a superb voice-controlled jukebox with all the world's music at your demand.
I use this set-up throughout the house, including in the bathroom, and here it is in the kitchen:
The Echo is just under the bottom right corner of the TV on the fridge, and the amp and speakers are on top of the white cupboards. The amp and bluetooth receiver are powered on by a LightWaveRF socket which is controlled by Domoticz (more on that later).
Saying "Echo, turn on Kitchen" causes the TV, amp and bluetooth to be powered up, and the Echo automatically connects to the amp.
Saying "Echo, play Women in Pop" will cause the Spotify playlist "Women in Pop" to start playing on the amp.