We have explored the taxonomy of a VoiceXML document. The VoiceXML elements can also be categorized by function, as shown in Table 3-1, based on comments in the DTD. This partitioning can be summarized as follows:
Element types controlling how input is collected from the caller.
Element types controlling how audio is rendered to the caller.
Element types that perform telephony hardware operations.
Element types that define a dialog.
Element types that produce or handle real-time events.
Element types that define a form field.
Element types that control the execution flow of a VoiceXML application.
Element types that provide access to ECMAScript, native objects, ...