Accidentally entered into either safe mode or recovery mode (Xperia XZ2 Compact)
My previous phone had been a Pixel and I was familiar with holding down the volume down button and power button at the same time to take a screenshot. When I did this on my Xperia XZ2 Compact, The phone shut off and restarted to a mode where every notification on the phone has a voice assistant reciting it. The phone also functions more slowly. I would like to know what I have done to my phone and whether it is reversible.
The feature that you have activated is called Talkback and is a tool to help visually impaired users use their device.
There is a volume key shortcut setting in the device that will activate Talkback as the standard one if you press and hold both volume buttons at the same time for 3 seconds and I think that is what happened, as you can take a screenshot in our devices when using volume down and the power button at the same time, or if you press the power button > tap on "Take screenshot".
You can disable the volume key shortcut, or change what it starts in Settings > Accessibility > Volume key shortcut. Turn off "Use service" if you don't want the shortcut at all, or tap "Shortcut service" and choose a service from the list.
To turn of the mode you are in now, go to Settings > Accessibility > Talkback > Off. The device acts a bit different in this mode, so if you want to swipe, you have to use two fingers instead of one and when you want to tap on something to, tap once and you will see a green square around the option > double tap with your finger.
Let us know if you were able to disable the Talkback mode!