There are two speaking 'characters' in AUI: the Narrator and the Chanter.
The Narrator provides immediate feedback and a description of what's going on.
The Chanter's job is more subtle — it makes noise from time to time so a user won't forget that the computer is on (and will be able to tell where it is), and it speaks the name of the active activity so the user won't forget.
I think of that as being analogous to the label at the top of this screen identifying the active browser. As long as things are happening (mouse clicks, mouse activity, etc.) the chanter doesn't say anything.
And at the request of some people who found it crazy-making, the Chanter can be turned off completely.
Both of them can be configured in the Preferences activity:
- Personality
Any of several voices may be chosen for each character. They all come from the standard Apple collection (with some of the really silly ones omitted from the list), and provide personalities ranging from male or female children and adults to an old guy who sounds like he's about to fall asleep (Ralph, the default Chanter voice) to a very nicely done, intelligible young man, Alex, the default Narrator.
- Speaking speed
The rapidity of the characters' speech can be set individually from a little slower than normal sounding speech to so fast that I can't understand it. I have it on good authority that B/VI people understand it with no trouble at all...
- Volume
The speaking volumes can also be controlled individually.