You'll need to record a trigger phrase - such as "Ok Google" - since it's apparently unable to pull in a pre-existing voice command you may have already set up on another Assistant-powered device. The update adds a useful new Siri Shortcut support using which one can use Siri to trigger Google Assistant. Google is using every trick in the book to try and redress the balance though, and with a new update to the Google Assistant app it is using Siri Shortcuts as a way to get voice activation for Google Assistant into iOS.
That said, you don't have to say, "Hey Siri, OK Google".
Taking advantage of Siri Shortcuts, iOS users can now communicate with Google Assistant without leaving Apple's assistant.
Well, this is insidious: Google has figured out a way to subvert Siri so that you can use it to summon Google Assistant on the iPhone instead. All you need to do is pick up your iPhone or iOS device and say, "Hey Siri".
Google takes a Shortcut to link Assistant and Siri
Once done, you can trigger Assistant by simply saying "Hey Siri" followed by the voice phrase you recorded. With Siri Shortcuts, Google is minimizing at least one such limitation. Then you should see a card at the top that has a button to "Add to Siri". Google Assistant will then pop up ready to accept your commands.
The process is more complex than usual because it requires several intermediate steps until Google Assistant begins to interpret what the user says.
Google released an exciting update for its Assistant iOS app today, bringing support for Siri shortcuts and, for the first time, opening lines of communication between the two competing assistants.
You'll probably want some wireless headphones to go with your new smartphone, so you should consider Google's $160 Pixel Buds, especially since you can get a pair for $50 less.