Have you purchased Nuance?
You have to configure the VXML Gateway per instructions in CVP
Configuration Guide
In Studio Project/Properties/CallStudio/General settings, specify that
you're using the Gateway: Nuance
Then you can use Digits, Number, Currency, Date, Time, Menu elements to
collect caller input using voice or dtmf.
If using the Form element, you can use VoiceGrammar or DTMFGrammar to
specify URLs pointing to external grammars.
If using Form element, you can specify what the caller can say or press
using VoiceKeyword and DTMF Keypress settings (this is broken in 10.5
though)