Hey there Iconmae,
Thanks for reaching out to Apple Support Communities. I understand your husband’s iPhone is using the Dictation feature unexpectedly. I’ll be happy to help with this.
What you’re describing sounds like the Dictation feature as seen here:
Use Dictation on your iPhone, iPad, or iPod touch
Go to Settings > General > Keyboards and turn off Enable Dictation. Restart his iPhone and see if the issue returns:
Restart your iPhone, iPad, or iPod touch
If that doesn’t help, go to Settings > Bluetooth and turn that off to ensure this isn’t related to some device that is connected there.
If the issue continues, back up his iPhone and restore his iPhone to factory settings using the steps from these links:
How to back up your iPhone, iPad, and iPod touch
Restore your iPhone, iPad, or iPod to factory settings
See if the issue returns. If it doesn’t restore the backup to his iPhone and test once more:
Restore your iPhone, iPad, or iPod touch from a backup
Cheers