Accidentally turned on talkback
I had this problem with LG Android also - accidentally turned ON talkback. Here's how i got it turned off.


You can swipe by using two fingers
Tap once on settings
Then double tap on settings to activate
Repeat process on the following..
General/Accessability/Vision
In Vision you should see Talkback where you can turn it off (again by using the same single, then double tapping process)