Do you need to use speech to select menu options for example? Or just convert user speech to text and save it somewhere?
If you need to select menu options (like ASR, automatic speech recognition), then it is not possible, because the underlying IVR doesn't support ASR. But if you need to convert user speech to text and do something with the text, you could use the Microsoft Speech API into a .NET DLL, and call that DLL from an External Code Execution component. You can record the audio first, and the use the audio from the wav file in disk to convert speech to text...
Regards,