Talkback is when you hear yourself, when you key up. It's a little transister that relays what is transmitted, back through the external speaker. Some of the higher priced radios have an on/off switch, and talkback is installed from the factory. Or, if you don't have talkback, a CB guy can solder one in your radio. I've got talkback in mine. It helps me to know how much echo I've got.