Using Voiceover at login screen I wish for my pupil to be able to login using VoiceOver. There are three user accounts and VoiceOver doesn't read them. We have used System Preferences to use VoiceOver at login and changed to username / password for input. We can't tab between the two and can't hear VoiceOver for caps lock.
With no concrete details or info whether you’ve gone through troubleshooting and can reproduce this after a reboot, here are some triage steps. 


Check the voiceover guide to you know which key shortcuts can start the speech: https://help.apple.com/voiceover/info/guide/10.12/#/vo2755
Restart the Mac and go through the basic steps once you are logged in to a new test account - https://help.apple.com/voiceover/info/guide/
Once you’re sure voiceover is working in the new test account log out to the home screen and retest.