@Fragglemuppet I'd say go into ctrl+nvda+v, shift+tab past the OK button, and you'll land on the modes selector. uncheck "Off" and "Beeps", so your only modes are "On" and "On-demand". Now if you press nvda+s, you'll change speech so it responds to keyboard commands like nvda+t and nvda+f12, but doesn't randomly talk unless you specifically request information.