Amazon Says Alexa Listens for Wake Words, Not Every Word

Engadget reported that more than 600 million Alexa-enabled devices have been purchased worldwide since the service's initial release. That figure does not directly translate into active users, but it helps explain persistent privacy questions. Amazon recently announced several new products, including a new line of tablets, many of which involve Alexa. The company is also continuing to roll out Alexa+, which is designed for additional real-world applications.

Amazon's explanation draws a distinction between passive wake-word detection and active listening. According to the report, Alexa does not listen verbatim to every word spoken around it. It listens for acoustic patterns matching its wake word, comparable to hearing a conversation with earplugs in: the exact words may be unclear, but a familiar sound pattern such as one's name can still be recognized. Once the wake word is recognized, the device switches to active listening to respond to a request, and only then does it record audio or send it to the cloud.

Amazon says this is the balance it has found between privacy and the conversational assistance Alexa is meant to provide. If the device were not listening on some level, it could not know when a user is addressing it. The report says Alexa devices are designed to record as little audio as possible, saving only direct conversations with the device.

Users who want to limit listening can mute the microphone. On most Amazon-made Alexa devices in the Echo lineup, the mute button is on top and marked with a microphone with a slash through it. A red light indicates that the microphone is muted. The report notes that this works against the device's intended hands-free use, but it is a direct option for privacy concerns.

Recording settings can also be adjusted. In the Alexa app, users can tap the three lines, select Alexa Privacy, choose Manage Your Alexa Data and then select Voice Recordings and Transcripts. The report says four options are available: saving recordings for three months, saving for 18 months, saving until the user deletes them, or not retaining them at all. On the Alexa data screen, users can also toggle how other data is saved, including smart-home device history and detected sounds history. Some devices allow voice deletion commands such as "Alexa, delete everything I said today" or "Delete my entire voice history"; this does not work with devices running Alexa+ or Amazon Kids.

The report says these settings apply only to Amazon's cloud. If Alexa is used with third-party devices such as robotic vacuums or smart TVs, those companies may still have access to history after deletion. Deleting voice recordings can also affect personalization because the device cannot maintain a voice profile for the user.

Editor's Summary Amazon says Alexa listens for wake-word acoustic patterns and records only after a request, while users can mute microphones and adjust or delete voice recordings. The controls apply to Amazon's cloud, and third-party devices may retain histories, so privacy depends partly on how Alexa is used.