Why Siri is not talk me?

Perhaps one of these articles will help:

Get help with Siri on your iPhone, iPad, or iPod touch - Apple Support

Get help with the microphones on your iPhone, iPad, and iPod touch - Apple Support

If Siri still doesn't work, contact Apple Support.

It would also be useful to know something about if this is a intermittent issue, or if it's happening all the time. Seems like an issue that might be fixed by doing a restart or a forced restart on your phone. 🙂