How to turn off Parental Controls logout voice announcement in MacOS High Sierra

Does anyone know how to turn off Parental Controls logout voice announcement in MacOS High Sierra? It looks like this has been a question over the years without an answer. The scenario: you have an account for your child on your Mac which you have restricted with Parental Controls. In Parental Controls, you can set a time schedule of when your child can use their account and when they can't. If they are logged into their account when the 'blackout' time for their account approaches, the Mac gives (loud and annoying) voice announcements a few minutes in advance and immediately before the account is automatically logged out, including a (ridiculous) "T minus 10..9...8-style countdown. I've checked my settings and no other voice announcement settings are turned on, and I don't see a related setting within Parental controls.

Props to the person who has figured out how to disable these voice announcements and shares their method here, especially if it doesn't involve using Terminal, deleting preference files, etc..