22. A method for automatically planning a sentence in an automated dialog system based on communicative goals related to information needed to be obtained from a user, comprising: generating and storing via a processor a plurality of sentence plans based on the communicative goals and information related to a set of interactions between the user and the automated dialog system and on a dialog history database comprising previously gathered dialogs and the present dialog to yield generated sentence plans, wherein each sentence plan of the generated sentence plans comprises an unordered set of elementary speech acts encoding the communicative goals, each speech act assigned a canonical lexico-structural representation, and wherein each sentence plan of the generated sentence plans is a viable and potentially usable prompt in response to a single communication from the user; ranking, independent of the user, the generated sentence plans using a set of learned rules; selecting a highest ranked sentence plan to yield a selected sentence plan; realizing the selected sentence plan by applying a set of linguistic rules to yield a realized sentence plan; converting the realized sentence plan from text to speech to yield a converted sentence plan; and outputting the converted sentence plan to the user to yield an output sentence plan, wherein each needed communicative goal of the communicative goals is addressed by the output sentence plan.
22. A method for automatically planning a sentence in an automated dialog system based on communicative goals related to information needed to be obtained from a user, comprising: generating and storing via a processor a plurality of sentence plans based on the communicative goals and information related to a set of interactions between the user and the automated dialog system and on a dialog history database comprising previously gathered dialogs and the present dialog to yield generated sentence plans, wherein each sentence plan of the generated sentence plans comprises an unordered set of elementary speech acts encoding the communicative goals, each speech act assigned a canonical lexico-structural representation, and wherein each sentence plan of the generated sentence plans is a viable and potentially usable prompt in response to a single communication from the user; ranking, independent of the user, the generated sentence plans using a set of learned rules; selecting a highest ranked sentence plan to yield a selected sentence plan; realizing the selected sentence plan by applying a set of linguistic rules to yield a realized sentence plan; converting the realized sentence plan from text to speech to yield a converted sentence plan; and outputting the converted sentence plan to the user to yield an output sentence plan, wherein each needed communicative goal of the communicative goals is addressed by the output sentence plan. 26. The method of claim 22 , wherein the communicative goals comprise confirming information previously obtained from the user.