4. An information extraction system for extracting information from a natural language speech input using a computer, comprising: a speech recognizer, including a structured language model, receiving the natural language speech input and generating a textual representation of the natural language speech input based on language modeling by the structured language model, the structured language model accessing a semantic schema having a template with a structure of frames that corresponds to one or more pieces of information to be extracted for an application program and parsing the textual representation, generating a plurality of parse hypotheses, to obtain one or more candidate semantic parse trees, each of the parse hypotheses being constrained during generation, by the template in the semantic schema so that all parse hypotheses that do not match the complete structure of frames in the template are discarded during their construction so that each candidate semantic parse tree obtained by the structured language model matches the structure of frames and all parse hypotheses which do not match the complete structure of frames in the template are rejected, wherein each candidate semantic parse tree has a structure with a semantic frame label and one or more semantic slot labels corresponding to constituents of the textual representation, the semantic frame and slot labels identifying the information to be extracted, and wherein a selected candidate parse includes head words and semantic labels that are used to predict a next word in the natural language input, to obtain an overall parse for the natural language input; and a processor, being a functional element of the computer, activated by the speech recognizer to facilitate parsing of the textual representation.
4. An information extraction system for extracting information from a natural language speech input using a computer, comprising: a speech recognizer, including a structured language model, receiving the natural language speech input and generating a textual representation of the natural language speech input based on language modeling by the structured language model, the structured language model accessing a semantic schema having a template with a structure of frames that corresponds to one or more pieces of information to be extracted for an application program and parsing the textual representation, generating a plurality of parse hypotheses, to obtain one or more candidate semantic parse trees, each of the parse hypotheses being constrained during generation, by the template in the semantic schema so that all parse hypotheses that do not match the complete structure of frames in the template are discarded during their construction so that each candidate semantic parse tree obtained by the structured language model matches the structure of frames and all parse hypotheses which do not match the complete structure of frames in the template are rejected, wherein each candidate semantic parse tree has a structure with a semantic frame label and one or more semantic slot labels corresponding to constituents of the textual representation, the semantic frame and slot labels identifying the information to be extracted, and wherein a selected candidate parse includes head words and semantic labels that are used to predict a next word in the natural language input, to obtain an overall parse for the natural language input; and a processor, being a functional element of the computer, activated by the speech recognizer to facilitate parsing of the textual representation. 5. The system of claim 4 and further comprising: a ranking component ranking the candidate semantic parse trees generated by the structured language model.