Methods and apparatus for generating dialog state conditioned language models

• US 7,143,035 B2
• Filed: 03/27/2002
• Issued: 11/28/2006
• Est. Priority Date: 03/27/2002
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Visweswariah, Karthik, Printz, Harry W., Monkowski, Michael Daniel, Dharanipragada, Satyanarayana
• Primary Examiner(s): Lerner, Martin
• Application Number:
  US10/107,723
• Publication Number:
  US 20030187648A1
• Time in Patent Office: 1,707 Days
• Field of Search: 704/231, 704/236, 704/238, 704/243, 704/245, 704/251, 704/256.3, 704/257, 704/270, 704/275, 704/244
• US Class Current: 704/244
• CPC Class Codes: G10L 15/183 using context dependencies, e.g. language models
• CPC Class Codes: G10L 15/197 Probabilistic grammars, e.g. word n-grams
• CPC Class Codes: G10L 2015/228 of application context

Abstract

Techniques are provided for generating improved language modeling. Such improved modeling is achieved by conditioning a language model on a state of a dialog for which the language model is employed. For example, the techniques of the invention may improve modeling of language for use in a speech recognizer of an automatic natural language based dialog system. Improved usability of the dialog system arises from better recognition of a user'"'"'s utterances by a speech recognizer, associated with the dialog system, using the dialog state-conditioned language models. By way of example, the state of the dialog may be quantified as: (i) the internal state of the natural language understanding part of the dialog system; or (ii) words in the prompt that the dialog system played to the user.

Claims

1. A method for use in accordance with a dialog system, the method comprising the steps of:

generating at least one language model, the at least one language model being conditioned on a state of dialog associated with the dialog system; and

storing the at least one language model for subsequent use in accordance with a speech recognizer associated with the dialog system;

wherein the step of generating the at least one language model conditioned on a state of dialog associated with the dialog system further comprises the steps of;

caching words in a prompt presented to a user by the dialog system;

building a unigram model on the cached words; and

interpolating the unigram model with a baseline model.

2. The method of claim 1, wherein the baseline model is a trigram language model trained from available training data for a domain of the dialog system.

3. Apparatus for use in accordance with a dialog system, the apparatus comprising:

at least one processor operative to generate at least one language model, the at least one language model being conditioned on a state of dialog associated with the dialog system; and

memory, coupled to the at least one processor, for storing the at least one language model for subsequent use in accordance with a speech recognizer associated with the dialog system;

wherein the operation of generating the at least one language model conditioned on a state of dialog associated with the dialog system further comprises;

(i) caching words in a prompt presented to a user by the dialog system;

(ii) building a unigram model on the cached words; and

(iii) interpolating the unigram model with a baseline model.

4. An article of manufacture for use in accordance with a dialog system, comprising a machine readable medium containing one or more programs which when executed implement the steps of:

generating at least one language model, the at least one language model being conditioned on a state of dialog associated with the dialog system; and

storing the at least one language model for subsequent use in accordance with a speech recognizer associated with the dialog system;

wherein the step of generating the at least one language model conditioned on a state of dialog associated with the dialog system further comprises;

(i) caching words in a prompt presented to a user by the dialog system;

(ii) building a unigram model on the cached words; and

(iii) interpolating the unigram model with a baseline model.

5. A data structure for use in accordance with a dialog system, the data structure comprising:

at least one language model, the at least one language model being conditioned on a state of dialog associated with the dialog system, and the at least one language model being for subsequent use in accordance with a speech recognizer associated with the dialog system;

wherein the at least one language model is generatable by;

(i) caching words in a prompt presented to a user by the dialog system;

(ii) building a unigram model on the cached words; and

(iii) interpolating the unigram model with a baseline model.

6. A dialog system, comprising:

at least one language model, the at least one language model being conditioned on a state of dialog associated with the dialog system, wherein the at least one language model is generatable by;

(i) caching words in a prompt presented to a user by the dialog system;

(ii) building a unigram model on the cached words; and

(iii) interpolating the unigram model with a baseline model; and

a speech recognizer for recognizing speech utilizing the at least one language model.