I noticed last night when using the Siri female voice voice number 4 that the pitch changes when you ask certain questions. For example it will change when you ask it if you have any messages the pitch will get lower and the Siri voice will become deeper. I have deleted my Siri and dictation history and I’ve also turned off Siri and turned it back on only to have the same issue happen again. I reported this to Apple Accessibility and they said they will send it up to the engineering in hopes that this issue gets resolved in a future update.