This is the 'Stammer Jammer', which was invented over 20 years ago (maybe 30 years ago), and was a simple device that used a microphone, and headphones to play a noise into your ear, whenever you started to talk.
On the market today (2023) there are three or four devices which play a delayed and higher pitch version of your own voice into your ear. I have been looking at the reviews of these devices, ...