It can be quite embarrassing when you accidentally trigger Siri, particularly during an online meeting. Apple’s virtual assistant Siri is designed to speak even when your iPhone is set to silent. This quick guide will show you how to change this.

Siri & Search

Navigate to your iPhone settings
Tap Siri and Search
Select Siri Responses
Select When Silent Mode is Off

After making this change, Siri will no longer speak when your iPhone is set to silent, unless you use the “Hey Siri” prompt, or are connected to a Bluetooth device/CarPlay.

Source: https://www.howtogeek.com/255788/how-to-silence-siri-with-your-iphones-ring-switch/