https://wccftech.com/patent-suggests-apples-siri-is-learning-how-to-yell-and-whisper/

Apple is constantly working on improving Siri with yelling and whispering being one of the things we might see in a future update.

Presently, whatever you ask Siri, you’ll get a response in a pre-set noise level and no variations in tone whatsoever. But according to a patent application, via AppleInsider, Apple will teach Siri a new trick, where the voice assistant could respond with a yell or a whisper based on the environmental conditions.