Yes, you can change Siri's behavior and even its trigger phrase with iOS 18 (using Vocal Shortcuts) for personalized commands, though you can't completely rewrite core commands like "Hey Siri," but you can create custom actions through the Shortcuts app or Accessibility settings for specific tasks. You can customize its voice, language, and set up automations to make it more useful for your needs.
Go to Settings and select Accessibility. Select Voice Control, then select Customize Commands. Select Create New Command, then enter a phrase for your command.
"Lumos" is the wand-lighting charm. It will illuminate the tip of the caster's wand so that they can see in the dark. Here, the end of the wand is your iPhone's rear flash. So saying, "Hey Siri, Lumos," will turn on your flashlight (or torch).
Unfortunately, you cannot change Siri voice to Darth Vader.
Tap Voice at the top to see the available voices for the selected language. Many voices have enhanced versions, but they may not be downloaded. If a voice has a download icon to the right, tap that icon to download the voice. Once a voice is downloaded, tap it again to set it as the systemwide voice.
Navigate to Siri & Search Settings on Your Device
This is where all Siri-related customization happens. From here, you can manage Siri's voice, language, and other preferences. Make sure you're in the right section before moving forward.
Starting in iOS 13 set to American English, if a user says, "Hey Siri" without following up with a question, Siri can respond with "Huh?", "Uh-huh", or "Mm-hmm?" instead of "Yes?".
When you say "108" or "Siri 108" in to your iPhone, it displays that it will call emergency services in five seconds. If you don't cancel before the call is made, your phone dials 9-1-1.
Did you know that if you say 'Lumos! 'to Siri on iphone or to google on Android, the flashlight turns on and 'Nox! ' to turn it off!
However, if you say one thing in particular to Siri, your device will crash. By going to your phone's voice input and saying "hyphen" repeatedly, the device will crash.
One shortcut that became popular was saying “Hey Siri, I'm getting pulled over.” This shortcut would then record your interaction with the police and send it directly to a predestined contact, along with your current location.
In case you don't know, Siri's trigger phrase is "Hey, Siri", meaning when you say that out loud (and the option is enabled), the virtual assistant will start listening to your commands. The thing is, in order for it to hear "Hey, Siri" in the first place, it actually listens all the time.
On iPhone and iPad
Open the Settings app on your iPhone or iPad. Scroll down and tap Siri & Search. Now tap Siri Voice. You'll see different voice options, including accents and genders.