Designing Effective Speech Interfaces

Forgiveness

Forgiveness, the nineteenth law, is: The interface will make actions recoverable.

Human Factors

Examining forgiveness in a system means examining errors. Humans make mistakes as they are using machines. They make mistakes when they use any interface, and speech interfaces are no exception. In fact, speech interfaces have some of the highest error rates compared to other interfaces, such as GUIs, because of the characteristics and limitations of the technologies.

Speech interfaces have some of the highest error rates compared to other interfaces, such as GUIs, because of the characteristics and limitations of the technologies.

Sometimes mistakes happen because users do not understand what they are supposed to do. This may stem from actual user error. Often, however, errors happen because the interface is at fault—one or several of the other laws have been violated, making the interface hard to learn, understand, or use.

Sometimes mistakes happen because the user pushes a wrong button, or chooses something other than what they meant to choose. For example, the user may say “two” to a menu, when they really meant to say “three.” The user intended to say or do one thing, but actually said or did something else.

Technology Considerations and Implications

We must assume that errors will occur, and therefore build mechanisms into the interface to handle the errors in as forgiving a way as possible.

Although speech recognition technology and interfaces have improved greatly ...