iOS Tip 115 - Mute Siri

Enable Siri Muting & Unmuting with the Hardware Switch on iPhone & iPad

Open Settings and go to “General” then to “Siri”. Choose “Voice Feedback” and select “Control with Ring Switch” (yes, the Mute switch on the side of the iPhone and iPad is referred to as the ‘Ring Switch’ here, but it’s the mute button you know and love)
Allow mute switch to silence Siri voice feedback

Leave Settings and activate Siri with the mute switch enabled, Siri will respond in text and on screen only, without blabbing the answer to the world
Siri works exactly the same as it did before, but you won’t hear any voice feedback if the mute switch is toggled on, even if you use the Hey Siri command handsfree from afar.