A Spoken dialog system is a dialog system

Dialog system

A dialog system or conversational agent is a computer system intended to converse with a human, with a coherent structure. Dialog systems have employed text, speech, graphics, haptics, gestures and other modes for communication on both the input and output channel.What does and does not constitute...

 delivered through voice. It has two essential components that do not exist in a text dialog system: a speech recognizer and a text-to-speech module.

Components

• Speech recognizer
• Text-to-speech
• Response generator, which uses techniques beyond natural language generation
  Natural language generation
  Natural Language Generation is the natural language processing task of generating natural language from a machine representation system such as a knowledge base or a logical form...
  
  . A response generator has to take domain information into account. Different wording of saying the same thing to the user will yield very different results. In call center application, response design is a very important art.
• dialog manager
• knowledge base
  Knowledge base
  A knowledge base is a special kind of database for knowledge management. A Knowledge Base provides a means for information to be collected, organised, shared, searched and utilised.-Types:...
  
  
• Natural language understanding
  Natural language understanding
  Natural language understanding is a subtopic of natural language processing in artificial intelligence that deals with machine reading comprehension....
  
  

Types of Systems

Spoken dialog systems vary in their complexity. In general, the informational dialog system is the most simple one, and it gradually goes up to the most complex type, the entertainment dialog system.

• Informational: Examples include stock quotes, credit card and bank information. This also include Google 411 and Tellme directory assistance.
• Transactional: Examples include magazine subscription, and bank transaction.
• Diagnostic: Technical support.
• Educational/Tutoring: Tutoring system for physics and language learning.
• Entertainment and chatting