The xml tag identifies it, so extensions and MIME types don't seem to be important. A VoiceXML document contains one or more forms, which are similar to HTML forms. You might also think of them as pages or nodes in a state diagram. When using a VoiceXML application, you are in one form at a time. You can transition to other forms, inside or outside of the current document, using a goto tag.
Execution begins with the first form.
Without a goto tag, control passes to the next form in the document. Forms contain one or more sets of block tags, which, in turn, hold executable content, such as audio tags. The audio tag converts the text it contains into spoken words. The recorded audio is referred to with an URL, and must be a .wav file. It's based on ECMAscript , a standard developed from Netscape's JavaScript.