How to get VoiceOver on the login screen?

Use Command + F5 to turn on VoiceOver. If that doesn't work, try command + function + F5.

command f5 is all that seams to work for me.

Here are the steps to have voiceover start during login.
1.
Go to system preferences.
2. select users and groups.
3. Click the lock to make changes and key in your password. The loc can be found by pressing voiceover right arrow until hearing "click the lock to make changes".
4. Voiceover left arrow to return to the group that says: "users groups and login options and interact with it.
5. Once you've interacted with the group go to login options and stop interacting with the group.
6. Pressing voiceover rightarrow move to "use voiceover on the login screen" and check the box.
7. Press command-W to close the preferences window.
8. once the machine logs in press command-f5 to turn on voiceover.
Now each time you boot the machine voiceover should appear on the login screen and also when your user is booted up.

To get vo on the log on screen for good, after you are logged in do the following.

1. Go to the doc and go to system prefs.
2. Go to users and groups.
3. Go to the last item in the table, then vo right to unlock system prefs. You will need to enter a password
4. After you unlock your system prefs, check the use voiceover at the log on screen. I also have it log me on at start up as I'm the only one who uses the computer.

Hope that helps a bit.