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5 Tips to a Better VUI

Use smart re-prompting
Smart re-prompting means paying attention to the flow of prompts when a no-input or no-match occurs. If a question page opens with the following prompt: "Great! Now, how many cigarettes do you smoke each day?" and the caller says nothing in response, a smart re-prompt would be something like, "Sorry, I didn't hear you. Please say a number between 1 and 100. How many cigarettes do you smoke each day?" A not so smart re-prompt would say, "Sorry, I didn't hear you. Please say a number between 1 and 100. Great! Now how many cigarettes do you smoke each day?"

To avoid the occurrence of such jarring interactions, make sure that for pages that open with dialog markers (e.g., "Great!" "Now" "First" "One more thing" etc.), the re-prompt on the no-input and the no-match is turned off. Also make sure that the prompts for the no-input and the no-match contain the information the caller will need to provide the correct input.

Associate Site Variables with different versions of a Question Page
Site Variables provide the voice developer with a powerful device for crafting context sensitive Question Pages. Prior to Site Variables, a Question Page doubled both as the component for soliciting information and the component for storing that information. This forced the developer to write elaborate error strategies to account for the various contexts of failure, or to work with numerous Question Pages and resolve the need to have them all point to the same variable through a back-end script. This often resulted in inconsistent error strategies across Question Pages.

This technique spares the developer the pain of having to create no-input and no-match prompts with wording that tries to accommodate various contexts of entry. Instead, the prompts can focus on the error and leave the re-prompting to the main prompt in the second Question Page.

This technique can also be used in situations where the application may have a choice between using a verbose version of a question or a more compact one. For instance, the caller can be asked at the opening of the dialog if they are a first-time user of the system, and if they are, the application can route them to the more verbose version of the dialog.

Don't put into your prompt something that your grammar can't handle
Callers take their cue on how to respond and articulate their answers from the system they are interacting with. If the system uses slang or colloquialisms, chances are that the caller will mimic that behavior. Unless your system can handle "right on" for "yes" and "no dice" for "no," keep to the standard but predictable "yes" and "no."

Announce that you are about to give some information
In exchanges where a series of questions are asked of the caller and then some piece of information is provided (e.g., account balance), the system should always explicitly signal that it is about to provide the caller with the sought information. A simple sentence such as, "Here is your balance," "Your balance is," not only is a lot friendlier than coming back with a raw dollar amount, but serves as a cue to the caller to pay close attention to what the system is about to say.

In situations where the information about to be given will require special concentration from the caller, the system should use a longer phrase to prepare the caller. For instance, "I am about to give you your twelve digit tracking number. If you need me to repeat the number, just say, 'repeat'. Your tracking number is..."

Mark dialog sequencing
As mentioned in a previous column, -- "Why VUI Design is more Challenging than GUI Design" -- dialogs are both time-linear and unidirectional. This means that the system needs to constantly signal to its human partner that things are moving forward. Useful markers for achieving this are "and," "now," "next," and "finally."
If you are interested in professional help with optimizing your voice applications, feel free to contact me at bouzid@angel.com or call 1-888-MYANGEL (1-888-692-6435) and say "Ahmed Bouzid".