Personal Voice creates an artificial version of your voice to use on voice or video calls. It's intended to help those with disabilities speak, but anyone with select Apple devices can set it up.

You can also use the Alexa app and Alexa device to unlock voice-activated support when using your iPhone and other smart devices. To utilize these features, go to the device settings on your Alexa ...

You don't have to use your voice to speak to Siri.