Open Settings on your iPhone or iPad
Tap Notifications
Tap Announce Notifications
Turn off Announce Notifications
To stop it for AirPods only, leave Announce Notifications on and turn off the apps you do not want announced
Open Control Center
Press and hold the volume control
Tap Announce Notifications to turn it off
Open Settings
Tap Siri & Search
Tap Announce Notifications
Turn off Headphones or AirPods announcements if available
On Mac, open System Settings
Click Notifications
Turn off Announce Notifications if enabled
On Apple Watch, open Settings
Tap Notifications
Turn off Announce Notifications if enabled