Siri changes it's voice on its own to American Voice 1 : iOS 18.2 US

1. Is this your corporate iPhone? Then please contact the system administrator of your corporate
2. If it is your personal device, in that case, do you have any profile installed by your corporate/organisation/enterprise/School Management?
   1. Erase the profile added by you If you have installed a profile on your own --> Install or remove configuration profiles on iPhone - Apple ...
   2. Or please contact the system administrator of the organisation who provided the profile to you
3. If you want to turn on SSL trust for that certificate, go to Settings > General > About > Certificate Trust Settings. Under "Enable full trust for root certificates," turn on trust for the certificate. Apple recommends deploying certificates via Apple Configurator or Mobile Device Management (MDM). --> Trust manually installed certificate profiles in iOS and iPadOS ...

Users may change these Settings

1. Voice Selection: Users can manually change Siri’s voice from the settings. Options include various accents (e.g., American, British, Australian) and genders (e.g., male or female).
   1. Navigate to: Settings > Siri > Voice.
2. Language Change: Changing Siri's language in settings also changes the voice. Siri offers voices specific to the selected language.
   1. Navigate to: Settings > Siri > Language.