Use the dictation keyword phrase and menu
When Enhanced Dictation is on, you can enable a dictation keyword phrase that lets you start dictating and use dictation commands (also known as spoken commands) even when you’re not dictating text.
The dictation keyword phrase lets your Mac know that the next thing you say after the phrase will be a dictation command. For example, if the phrase is “Computer,” you can say “Computer, start dictating” (instead of pressing the dictation keyboard shortcut). If you enable advanced dictation commands, you can say commands like “Computer, switch to Finder” or “Computer, show numbers.”
When you enable the dictation keyword phrase, the Dictation menu is added to the menu bar. You can click the menu and use it to show or hide the list of available dictation commands, and change how your Mac listens for the commands.
Note: Before you can use any dictation commands, you must turn on Dictation.
Enable the dictation keyword phrase
Choose Apple menu > System Preferences, click Accessibility, then click Dictation.
Click “Enable the dictation keyword phrase.”
To use a keyword phrase other than Computer, type a new keyword. For best results, use a word or phrase that has three syllables or two to five words.
Change how your Mac listens for dictation commands
Listen for commands requiring the keyword phrase: Click the Dictation menu, then choose Listen With Required Keyword Phrase from the Dictation menu. This is the default setting (identified by Required Keyword Phrase: “keyword” in the menu ).
With this setting, your Mac listens for the keyword phrase to identify dictation commands. For example, to use the command “Move down” you must first say the keyword phrase, as in “Computer, move down.” If you simply say “Move down,” your Mac won’t perform the command.
Listen for commands without requiring the keyword phrase: Click the Dictation menu, then choose Listen Without Requiring Keyword Phrase.
With this setting, you don’t need to say the keyword phrase—your Mac is always listening for commands. For example, you can simply say “Move down” to have your Mac perform the command. Keep in mind that when the keyword phrase isn’t required, your Mac attempts to perform any command it hears; if it hears “move down” while you’re talking with a friend, it attempts to perform the command.
Note: If you log out or shut down the computer, the option is reset to the default (the keyword phrase is required) when you log back in or restart the computer. To dictate without the keyword phrase, choose Listen Without Requiring Keyword Phrase from the Dictation menu again.