https://www.techradar.com/news/alexa-devices-will-know-now-exactly-where-you-are-in-a-good-way

Amazon is moving a key bit of Echo software onto the cloud, meaning that all Alexa-enabled devices will be able to gauge the proximity of voice commands.

Anyone with more than one Alexa-enabled device in their home will know the tribulations of trying to speak to one device without activating another by accident.