Siri is learning a new trick with iOS 9. Actually, Siri is learning YOU with iOS 9. The latest version of iOS includes an update to allow Siri to learn to recognize and respond specifically to your voice.
Most mobile devices these days include some form of voice interaction, and with the launch of Windows 10 and Cortana even your PC will respond to verbal queues. The Xbox with Kinect responds to verbal commands. Amazon even introduced the Echo—a household appliance designed solely for the purpose of interacting with and responding to verbal commands.
With Google and Android you say “OK Google”. With Microsoft and Windows 10 you say “Hey Cortana”. With Apple and iOS you say “Hey Siri”. The issue, though, is that anyone saying the magic phrase can activate the device. There have been anecdotal reports of devices activating just because a commercial on television says “OK Google” or “Hey Cortana”.
Amazon addressed this dilemma by allowing you to customized the name of the Echo—thereby making your activation command unique in some way. Apple is striving to solve that problem in iOS 9 by having Siri learn to recognize only your voice, so that when a TV commercial or a guy sitting at the next table at Starbucks says “Hey Siri” your iOS mobile device will simply ignore it.
Current iOS devices only respond to the “Hey Siri” verbal command while plugged in to power and that won’t change with iOS 9. The new iPhone 6S and iPhone 6S Plus, however, will have the ability to respond to “Hey Siri” at all times—similar to the way voice interaction works on Android and Windows Phone devices.