Change Siri preferences on Mac
On your Mac, use Siri preferences to choose a language and voice, turn voice feedback on or off, and manage which apps Siri can learn from and make suggestions. See Use Siri on your Mac.
To open Siri preferences, choose Apple menu 
> System Preferences, then click Siri.
Enable Ask Siri | Use Siri to do everyday tasks, get quick answers and more. To stop using Siri, deselect the tickbox. (Siri continues to learn from and make suggestions in apps.) If you ask Siri something when the tickbox isn’t selected, you’re prompted to enable Siri. You must be connected to the Internet to use Siri. | ||||||||||
Listen for “Hey Siri” (available on some Mac models) Listen for “Hey Siri” on AirPods (available when you pair AirPods that support Hey Siri) | Select the tickbox to be able to say “Hey Siri” to start using Siri instead of clicking the Siri icon or using a keyboard shortcut. To stop using Hey Siri, deselect the tickbox. This option is only available if your Mac or paired AirPods support Hey Siri. If you turn off Ask Siri and then turn it on again later, you may need to set up Hey Siri again. | ||||||||||
Allow Siri when locked (available when Listen for “Hey Siri” is turned on) | Use Siri even if your Mac is locked or in sleep. Just say “Hey Siri”, then make your request. Depending on your request, you may need to unlock your Mac. | ||||||||||
Keyboard Shortcut | The default shortcut to ask Siri is to press and hold the Command key and the Space bar at the same time. To create your own shortcut, click the Keyboard Shortcut pop-up menu, choose Customise, then press the keys you want to use. For example, you could press Option-Z. | ||||||||||
Language | Choose the language and dialect that you want to use to ask Siri; Siri will use the same language and dialect to speak to you. Siri is not available in all languages or regions. | ||||||||||
Siri Voice | Choose a gender (and sometimes dialect) for Siri. Some languages may not have an alternative gender or dialect. | ||||||||||
Voice Feedback | Turn voice feedback (spoken responses) from Siri on or off. If you turn feedback off, the response from Siri is shown in the Siri window but is not spoken. | ||||||||||
Show Siri in menu bar | Show the Siri icon in the menu bar — another way to quickly ask Siri. | ||||||||||
Siri Suggestions & Privacy | Choose the apps for which Siri can make suggestions to you. For information about how Siri sends your spoken words to Apple and uses personal information such as your name, your contacts and other data to understand you better and recognise what you say, click About Siri & Privacy. | ||||||||||
If speech is difficult for you or you don’t want others to hear your Siri requests, you can type your requests to Siri instead of speaking them. See Siri Accessibility preferences.