On another note, you could record your own voice prompts as .wav files, import them into Interaction Designer using the prompt Editor (Built into the Play Prompt tool step), and then play them back using the Play Prompt or Play Prompt Phrase tool steps.
That is more work, especially if you change prompts often. See the Interaction Designer help, and look at existing handlers that use those tools to get some examples of how to do it.
Or, come to Basic Handlers class :-)