Today, Google is shipping a major update for Google Home: multi-user support. Up to six people will be able to connect their account to Google's voice appliance, which will then be able to identify each person just by listening to them speak. The Google Home app jumped the gun on this launch earlier in the month, but now the feature is actually rolling out.
After connecting their accounts, each user will have to go through the usual hotword training, reciting "OK Google" to the device three times. For future commands, Google Home will then call out the name of the person it detects before it gives a response. So if you ask "What's my day like?" Google Home will respond with "Good Morning [name]," and then rattle off the weather and calendar appointments. To start the setup process, look for the card that says "multi-user is available" in the Google Home app. Thanks to the way Google rolls out features, it might take a few days.
On-the-fly detection of voices sounds like a challenging problem to overcome. During the training process, your "OK Google" phrases are analyzed by a neural network, which Google says can "detect certain characteristics of a person's voice." Future "OK Google" commands are compared to the previous analysis, and Google Home decides if it's a match. Google notes, "this comparison takes place only on your device, in a matter of milliseconds."