Designing Effective Speech Interfaces

Flexibility

The twelfth law of Flexibility states: The interface will allow the user to adjust the design for custom use.

The goal of accommodation is to account for what 80 percent of the users need to do 80 percent of the time. Beyond this is flexibility so that you can take care of the other 20 percent.

Human Factors

In the law of accommodation we covered adjusting the interface to match the way users work. Flexibility involves letting users customize the interface for their own work. The goal of accommodation is to account for what 80 percent of the users need to do 80 percent of the time. Beyond this is flexibility so that you can take care of the other 20 percent.

Technology Considerations and Implications

Even if you design for what most people need most of the time, there are people and situations that have not been taken care of. Building in enough flexibility to take care of these situations means that you have built in ways to go beyond the 80 percent towards 90 or even 95 percent. It is unrealistic to assume you will be able to build in enough flexibility so that all people have all needs met, but you try to stretch that limit as far as it can go.

Examples of flexibility in speech interfaces include allowing barge-in so users can interrupt the system and take over the interaction, the ability to speak to a human at any time, and allowing users to customize menus.