What screen design is to graphical user interface design, conversation and prompting are to speech interface design. Taking care when designing the conversation and prompting will reduce errors and increase user satisfaction.
Use the word “say” when you want the user to speak, rather than “enter.” Use “enter” for key presses. If you want the user to speak the words “yes” or “no,” then use the phrase, “Say yes or no.” Here is an example:
“Do you want to transfer funds now? Say yes or no.”
“Do you want to transfer funds? Enter yes or no.”
Use as few words as possible between “say” and the command. This gives the user less to remember. Since speech interfaces place a heavy memory demand on users, it's important to be as brief as possible and still communicate clearly.
For example use: “Say yes or no.”
“Say the word yes or no.”
Avoid using a personal pronoun when asking the user to respond to a question. For example, use:
“Say your credit card number.”
“Tell me your credit card number.”
Using a personal pronoun places an extra word between the command (say) and the information the user is supposed to respond with (credit card number). To decrease the memory demand, use as few words as possible between the two elements. In addition, use the command “say” as it is clearer and more imperative than “tell.”