Hello SuwaneeJohn,
Thanks for reaching out to us for support. This is certainly not the experience that we want you to have with Siri on your iPhone, and we are going to do everything we can to help you. When you have a free moment, check out the thread below. The reason we ask you to give the steps in the thread a try is because they can potentially resolve your issue.
https://discussions.apple.com/thread/252525568?answerId=254774113022#254774113022
If you’re still experiencing the same problem after completing the steps via the link we provided, do not hesitate to reach back out to us so that we can continue troubleshooting with you.
Thanks for using the Apple Support Communities.
Cheers!