Controlling the “lost in space” problem

Users rarely get lost when using simple, straightforward applications. When an application contains deeply-nested menus, though, the user can get disoriented, causing the interaction between the user and the application to break down.

Minimizing the number of nested menus

To help users avoid this “lost in space” dilemma, you should try to minimize the number of nested menus required to reach any given dialog state. In speech interfaces (as in visual interfaces), users are less likely to get lost in a broad structure as opposed to a deep structure.

Using audio formatting

In addition, you may want to consider using audio formatting to help orient the user. For example, you might play different introductory or background tunes for different modules of the your application.

Providing landmarks

Another technique to consider is providing auditory landmarks at key places in the application. For example:
System: You can make, change or cancel reservations. What would you like to do?
User: I'd like to make a reservation.
System: Making reservation (This is the landmark)