My wife updated her iPhone 6 Plus to iOS 9 and Siri worked fine up until today. Today if you ask Siri a question you can no longer hear her response. I went to settings and changed the language and it started working again. I changed it back to English and nothing. Any suggestions other than doing a reset? I have voice feedback set to always and before someone ask "Yes" I have the volume turned up and the phone isn't muted or connected to any bluetooth device.