With iOS 8, Apple introduced the "Hey Siri" wake phrase, so you can summon Siri without even touching your iPhone. If you turn this feature on, this means your iPhone's mic is always listening, waiting for the phrase "Hey Siri." Apple says this is processed locally on your iOS device, and it does not start recording until it hears "Hey Siri." Luckily, you don’t have to disable Siri completely to stop the “Hey Siri” feature. Here’s how to turn off the "OK Google" wake phrase: On Android, go to Settings >> Google >> Search & Now >> Voice and turn “Ok Google” detection off.

Source: Fox News October 01, 2017 11:03 UTC