8. The system of claim 7 , wherein the control messages are encoded using XML (eXtensible Markup Language) and wherein the control messages are exchanged using SOAP (Simple Object Access Protocol).
7. A distributed speech processing system, comprising: a client computing device executing a conversational application; and a server device in communication with the client computing device over a network, the server device providing an audio I/O processing Web service, which is programmable by control messages generated by the conversational application to provide audio I/O services for the conversational application and a speech engine Web service, which is programmable by control messages generated by the conversational application to provide speech processing services for the conversational application, wherein the audio I/O and speech processing Web services are programmed to perform audio processing tasks specified by the control messages but wherein the audio I/O and speech processing Web services perform said audio processing tasks by executing a flow control that is decoupled and independent from control of the conversational application.