System Preferences -> Accesibility -> Speech -> System Voice:Customize -> Check Whisper
-> Ok -> Close SP
Q: Why manually enable it? can't you just make a script?
A: If you want to enable it via AppleScript you can't use "System Events" to tell
"System Properties" what to do unless it's allowed by "Assistive app control" which is guarded by the user's password. The other alternative is to download the voice package to /System/Library/Speech/Voices/
but the folder is owned by root
with no write permissions and can't do anything without the password.