The approach described in this article makes use of the new element that is part of the VoiceXML 2.1 specification. I'm not clear on whether this approach is the same as AJAX, but it is indeed powerful.
Given the recent hype, I can understand the desire to characterize the functionality provided by the new 2.1 spec as emulating AJAX. But I think it’s important to point out that callers to a VoiceXML application probably don’t perceive page transitions in the same way that users of a visual web application do. There are ways to manage user reactions to these transitions within VoiceXML and users need to be aware of how to use them effectively.