Apparatus, method and computer readable memory medium for speech recognition using dynamic programming

• US 7,062,435 B2
• Filed: 07/26/1999
• Issued: 06/13/2006
• Est. Priority Date: 02/09/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tzirkel-Hancock, Eli, Keiller, Robert Alexander
• Primary Examiner(s): Dorvil, Richemond
• Assistant Examiner(s): ARMSTRONG, ANGELA A
• Application Number:
  US09/359,912
• Publication Number:
  US 20020032566A1
• Time in Patent Office: 2,514 Days
• Field of Search: 704/231, 704/236, 704/238, 704243-245, 704/251, 704/255, 704/257, 704/270, 704/275, 704/241, 704/272, 704/240, 704/250, 379/88.01, 379/88.02, 379/88.03, 379/88.04, 379/88.16, 379/67.1
• US Class Current: 704/241
• CPC Class Codes: G10L 15/12 using dynamic programming techniques, e.g. dynamic time warping [DTW]
• CPC Class Codes: G10L 2015/085 Methods for reducing search complexity, pruning
• CPC Class Codes: H04M 1/271 controlled by voice recognition
• CPC Class Codes: H04M 1/57 Arrangements for indicating or recording the number of the calling subscriber at the called subscriber's set at the operator set in a manual exchange H04M5/20
• CPC Class Codes: H04M 1/6505 storing speech in digital form
• CPC Class Codes: H04M 2201/40 using speech recognition
• CPC Class Codes: H04M 3/42204 Arrangements at the exchange for service or number selection by voice at the terminal H04M1/27
• CPC Class Codes: H04M 3/533 Voice mail systems
• CPC Class Codes: H04M 3/53383 Message registering commands or announcements; Greetings

Abstract

A method for matching an input pattern with a number of stored reference patterns using a dynamic programming matching technique is described. The reference patterns of a reference signal which are at the end of a dynamic programming path for a current input pattern are listed in an active list. The dynamic programming paths are propagated by processing the reference patterns on the active list, and a new active list is generated for the succeeding input pattern. The amount of processing required for each pattern on the active list is reduced by using a pointer which identifies the reference pattern which is the earliest in the sequence of patterns of the current reference signal listed on the new active list during the processing of a preceding dynamic programming path. In a second aspect, a speech recognition interface is used as a control system for a telephony system.

Claims

1. A control system for controlling a telephony system, comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling the telephony system, said speech recognition user interface comprising;

(i) means for receiving an input speech command;

(ii) means for storing a plurality of reference word models;

(iii) means for comparing the input speech command with the stored reference word models to generate a recognition result; and

control means, responsive to the recognition result generated by said speech recognition user interface, for controlling the telephony system in accordance with the input speech command;

where said control means controls the telephony system so as to reproduce a stored message using the recognition result generated by said speech recognition user interface;

wherein said message is stored with an identifier for identifying the caller that has left the message;

wherein said control means is operable to display a list of messages to be reproduced upon instruction to reproduce the message identified by said identifier; and

wherein said control means comprises means for predicting, using current system status information, what telephony service is wanted if the user inputs, via said speech recognition user interface, only the identifier of another user.

2. A system according to claim 1, wherein the control means further comprises interpretation means for interpreting the recognition result, which uses a factory set pre-stored dictionary.

3. A system according to claim 1, further comprising a plurality of storage means each associated with a respective user of the system, for storing the telephone numbers and associated identifiers of other users, whereby a user can designate another user of the system by speaking the corresponding identifier into said speech recognition user interface.

4. A system according to claim 1, wherein said speech recognition user interface comprises means for training said speech recognition user interface to recognize new speech commands.

5. A system according to claim 4, further comprising means for receiving a new input speech command comprising two or more whole words;

means for generating a word model for each of the words contained within the new input speech command, if they do not already exist; and

means for adapting the language model used to said speech recognition user interface to accommodate the new speech command.

6. A system according to claim 1, wherein each user has an associated set of reference word models.

7. A system according to claim 1, wherein said control means is provided in a local exchange.

8. A system according to claim 1 in combination with the telephony system, further comprising a number of communication devices for use by users of the telephony system, which are interconnected via a local exchange.

9. A system according to claim 8, wherein the control means is operable to communicate with each of the users via the respective communication devices, information representative of the current status of the system.

10. A system according to claim 8, wherein at least some of the communication devices have an associated display arranged to display messages representative of the operation corresponding to the input speech command, for a predetermined amount of time.

11. A system according to claim 8, wherein the local exchange is connected to the public exchange so that users connected to the local exchange can communicate with remote users on the public exchange and vice versa.

12. A system according to claim 8, further comprising a mail box facility which is operable to store messages for users of the system left by callers, when the users are unable to take the calls.

13. A system according to claim 12, wherein the mail box facility is operable to associate and store each message with the telephone number of the caller who left the message.

14. A system according to claim 13, wherein the speech recognition user interface includes a command that allows users to request the mail box facility to replay messages from a particular caller.

15. A system according to claim 14, wherein after replaying one of a plurality of selected messages a user can access other telephony services and return and replay the remaining selected messages after using those other telephony services.

16. A system according to claim 8, further comprising means for sharing use of said speech recognition user interface and said control means between a number of different users.

17. A system according to claim 8, further comprising a plurality of speech recognition user interfaces and a plurality of execution means for simultaneous use by a plurality of different users.

18. A system according to claim 1, wherein said control system is provided in a communication device.

19. A control system according to claim 1, wherein a message in the present ist of messages is reproduced when said list of messages to be reproduced is confirmed by the user.

20. A control system according to claim 1, wherein the control means is operable to control the telephony system to accept a new input speech command from the user while reproducing a message and is operable to use the recognition result of the new input speech command.

21. A control system according to claim 1, wherein the control means is operable to control the telephony system to notify the user when all messages identified by said identifier are reproduced.

22. A control system according to claim 1, wherein said speech recognition user interface is adapted to be able to recognise continuously spoken commands comprising a plurality of words defining a desired telephony service;

wherein said speech recognition user interface further comprises means for storing a language model which defines sequences of the reference word models which can be compared with the input speech command, in order to define allowed input speech commands; and

wherein said comparing means is operable to compare the input speech command with selected sequences of the reference word models, selected in accordance with the stored language model and wherein said control means comprises execution means for executing an operation corresponding to the input speech command.

23. A system according to claim 21, wherein the execution means further comprises:

(i) means for holding current system status information;

(ii) means for checking that the operation corresponding to the speech command does not conflict with the current system status information; and

(iii) means for requesting the user to confirm the speech command prior to execution if said checking means determines that the input speech command does not conflict with said current system status information, and

wherein a buffer is provided for buffering new system status information which is generated whilst said execution means awaits user confirmation.

24. A mail box facility for use with a telephony system, comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling the mail box facility, and for outputting a recognition result based on comparing the input speech commands with pre-stored reference models;

control means, responsive to the recognition result output from said speech recognition user interface, for controlling the mail box facility in accordance with an input speech command;

storage means for storing messages left by callers, when the users are unable to take the calls,

receiving means for receiving information of the callers via said speech recognition user interface;

reproducing means for reproducing the messages left by the callers identified by the information received by said receiving means; and

second storage means for storing a pointer that points to a last message reproduced by said reproducing means.

25. A telephony system comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling telephony services provided by the system, said speech recognition user interface comprising;

(i) means for receiving an input speech command;

(ii) means for storing a plurality of reference models; and

(iii) means for comparing the input speech command with the stored reference models to generate a recognition result; and

execution means, responsive to the recognition result generated by said speech recognition user interface, for executing an operation corresponding to the speech command,

wherein each user of the system is identified by a telephone number and an associated identifier, and wherein said execution means comprises;

means for receiving data identifying a current status of the telephony system; and

means for predicting a desired telephony service using the current system status data;

wherein if the user input command identifies a telephony service, then said execution means is operable to provide the desired telephony services identified in the input speech command; and

wherein said execution means is operable to predict a desired telephony service using said predicting means and said current system status data, if said input speech command does not identify a desired telephony service.

26. A system according to claim 25, wherein the current system status data comprises, for each user, data indicating:

who the user is currently speaking to, who the user is dialling, who is on hold, who is trying to ring that user, whether that user is playing messages, who has that user on old, and/or who has that user in a conference.

27. A system according to claim 25, wherein the desired telephony service comprises one of the following services:

setting up a call, transferring a call, holding a call, returning to a call, setting up a conference call, and message selection and replaying.

28. A control system for controlling a telephony system, comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling the telephony system, the speech recognition user interface comprising;

(i) an input terminal for receiving an input speech command;

(ii) a memory for storing a plurality of reference word models; and

(iii) a comparator for comparing the input speech command with the stored reference word models to generate a recognition result; and

a controller, responsive to the recognition result generated by said speech recognition user interface, for controlling the telephony system in accordance with the input speech command;

wherein said controller is operable to control the telephony system so as to reproduce a stored message using the recognition result generated by said speech recognition user interface;

wherein said message is stored with an identifier for identifying the caller that has left the message;

wherein said controller is operable to display a list of messages to be reproduced upon instruction to reproduce the message identified by said identifier; and

wherein said controller comprises a predictor for predicting, using current system status information, what telephony service is wanted if the user inputs, via said speech recognition user interface, only the identifier of another user.

29. A system according to claim 28, wherein said controller further comprises an interpreter for interpreting the recognition result, which uses a factory set pre-stored dictionary.

30. A system according to claim 28, further comprising a plurality of memory areas each associated with a respective user of the system, for storing the telephone numbers and associated identifiers of other users, whereby a user can designate another user of the system by speaking the corresponding identifier into the speech recognition user interface.

31. A system according to claim 28, wherein said speech recognition user interface comprises a trainer for training the interface to recognize new speech commands.

32. A system according to claim 31, further comprising an input for receiving a new input speech command comprising two or more whole words;

a word model generator for generating a word model for each of the words contained within the new input speech command, if they do not already exist; and

an adaptor for adapting the language model used by said speech recognition interface to accommodate the new input speech command.

33. A system according to claim 28, wherein each user has an associated set of reference word models.

34. A system according to claim 28, wherein said controller is provided in a local exchange.

35. A system according to claim 28 in combination with the telephony system, further comprising a number of communication devices for use by users of the telephony system, which are interconnected via a local exchange.

36. A system according to claim 35, wherein said controller is operable to communicate with each of the users via the respective communication devices, information representative of the current status of the system.

37. A system according to claim 35, wherein at least some of the communication devices have an associated display arranged to display messages representative of the operation corresponding to the input speech command, for a predetermined amount of time.

38. A system according to claim 35, wherein the local exchange is connected to the public exchange so that users connected to the local exchange can communicate with remote users on the public exchange and vice versa.

39. A system according to claim 35, further comprising a mail box facility which is operable to store messages for users of the system left by callers, when the users are unable to take the calls.

40. A system according to claim 39, wherein the mail box facility is operable to associate and store each message with the telephone number of the caller who left the message.

41. A system according to claim 40, wherein said speech recognition user interface includes a command that allows users to request the mail box facility to replay messages from a particular caller.

42. A system according to claim 41, wherein after replaying one of a plurality of selected messages a user can access other telephony services and return and replay the remaining selected messages after using those other telephony services.

43. A system according to claim 35, further comprising a multiplexer for time sharing the use of said speech recognition user interface and said controller between a number of different users.

44. A system according to claim 35, further comprising a plurality of speech recognition user interfaces and a plurality of command executioners for simultaneous use by a plurality of different users.

45. A system according to claim 28, wherein said controller is provided in a communication device.

46. A control system according to claim 28, wherein a message in the present list of messages is reproduced when said list of messages to be reproduced is confirmed by the user.

47. A control system according to claim 28, wherein the controller is operable to control the telephony system to accept a new input speech command from the user while reproducing a message and is operble to use the recognition result of the new input speech command.

48. A control system according to claim 28, wherein the controller is operable to control the telephony system to notify the user when all messages identified by said identifier are reproduced.

49. A control system according to claim 28, wherein said speech recognition user interface is adapted to be able to recognise continuously spoken commands comprising a plurality of words defining a desired telephony service and an identifier of another user;

wherein said speech recogniton user interface further comprises a memory for storing a language model which defines sequences of the reference word models which can be compared with the input speech command, in order to define allowed input speech commands; and

wherein said comparator is operable to compare the input speech command with selected sequences of the reference word models, selected in accordance with the stored language model and wherein said controller comprises a command executioner for executing an operation corresponding to the input speech command.

50. A system according to claim 49, wherein the command executioner further comprises:

(i) a memory for holding current system status information;

(ii) a checker for checking that the operation corresponding to the input speech command does not conflict with the current system status information; and

(iii) a prompter for requesting the user to confirm the speech command prior to execution if said checker determines that the input speech command does not conflict with the current system status information, and

wherein a buffer is provided for buffering new system status information which is generated whilst the command executioner awaits user confirmation.

51. A telephony system comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling telephony services provided by the system, the speech recognition user interface comprising;

(i) an input terminal for receiving an input speech command;

(ii) a memory for storing a plurality of reference models; and

(iii) a comparator for comparing the input speech command with the stored reference models to generate a recognition result; and

a command executioner, responsive to the recognition result generated by said speech recognition user interface, for executing an operation corresponding to the speech command,

wherein each user of the system is identified by a telephone number and an associated identifier, and wherein the command executioner comprises;

an input terminal for receiving data identifying a current status of the telephony system; and

a predictor for predicting a desired telephony service using the current system status data;

wherein if said user input command identifies a telephony service, then said command executioner is operable to provide the desired telephony service identified in the input speech command; and

wherein said command executioner is operable to predict a desired telephony service using said predictor and the current system status data, if the input speech command does not identify a desired telephony service.

52. A system according to claim 51, wherein the current system status data comprises, for each user, data indicating:

who the user is currently speaking to, who the user is dialling, who is on hold, who is trying to ring that user, whether that user is playing messages, who has that user on hold, and/or who has that user in a conference.

53. A system according to claim 51, wherein the desired telephony service comprises one of the following services:

setting up a call, transferring a call, holding a call, returning to a call, setting up a conference call, and message selection and replaying.

54. A method of controlling a telephony system comprising the steps of:

receiving an input speech command;

storing a plurality of reference word models;

comparing an input speech command with the stored reference word models to generate a recognition result; and

controlling the telephony system in accordance with the generated recognition result by executing an operation corresponding to the input speech command;

wherein said controlling step controls the telephony system so as to reproduce a stored message using the recognition result generated in said comparing step;

wherein said storing step stores said message together with an identifier for identifying the caller that left the message;

wherein said controlling step displays a list of messages to be reproduced upon instruction to reproduce the message identified by said identifier; and

wherein said controlling step comprises the step of predicting, using current system status information, what telephony service is wanted if the user inputs a speech command including only the identifier of another user.

55. A method according to claim 54, wherein said control step further comprises the step of interpreting the recognition result using a factory set pre-stored dictionary.

56. A method according to claim 54, further comprising the step of providing a plurality of storage means each associated with a respective user of the system, for storing the telephone numbers and associated identifiers of other users, whereby a user can designate another user of the system by inputting a spoken command comprising the corresponding identifier.

57. A method according to claim 54, wherein said controlling step comprises the step of predicting, using current system status information, what telephony service is wanted if the user'"'"'s spoken input command does not identify a desired telephony service.

58. A method according to claim 54, further comprising the step of training the language model to recognize new speech commands.

59. A method according to claim 58, further comprising the steps of:

receiving a new input speech command comprising two or more whole words;

generating a word model for each of the words contained within the new input speech command, if they do not already exist; and

adapting a language model used in said comparing step to accommodate the new speech command.

60. A method according to claim 54, wherein each user has an associated set of reference word models.

61. A method according to claim 54, wherein said control step is performed in a local exchange.

62. A method according to claim 54, wherein said controlling step communicates with each of the users via a respective communication device, information representative of the current status of the system.

63. A method according to claim 62, wherein at least some of the communication devices have an associated display, wherein said method further comprises the step of displaying messages representative of the operation corresponding to the input speech command, for a predetermined amount of time.

64. A method according to claim 54, further comprising the step of storing messages for users of the system left by callers, when the users are unable to take the calls, in a mail box facility.

65. A method according to claim 64, further comprising the steps of associating and storing each message in the mail box facility with the telephone number of the caller who left the message.

66. A method according to claim 65, further comprising the step of receiving a spoken input command requesting for the mail box facility to replay messages from a particular caller.

67. A method according to claim 66, wherein after replaying one of a plurality of selected messages, the method further comprises the steps of accessing other telephony services and returning and replaying the remaining selected messages after using those other telephony services.

68. A system according to claim 54, further comprising the step of sharing use of a speech recognition user interface between a number of different users.

69. A method according to claim 54, wherein a message in the present list of messages is reproduced when said list of messages to be reproduced is confirmed by the user.

70. A method according to claim 54, wherein the controlling step controls the telephony system to accept a new input speech command from the user while reproducing a message and uses the recognition result of the new input speech command.

71. A method according to claim 54, wherein the controlling step controls the telephony system to notify the user when all messages identified by said identifier are reproduced.

72. A method according to claim 54, wherein said receiving step receives an input speech command comprising a plurality of continuously spoken words defining a desired telephony service;

wherein the method further comprises the step of storing a language model which defines sequences of the reference word models which can be compared with the input speech command, in order to define allowed input speech commands; and

comparing the input speech command with selected sequences of the reference word models, selected in accordance with the stored language model and wherein said controlling step executes an operation corresponding to the input speech command.

73. A method according to claim 72, wherein the executing step further comprises the steps of:

holding current system status information;

checking that the operation corresponding to the input speech command does not conflict with the current system status information;

requesting the user to confirm the speech command prior to execution if said checking step determines that the input speech command does not conflict with the current system status information, and

buffering new system status information which is generated whilst the executing step awaits user confirmation.

74. A telephony method comprising the steps of:

providing a speech recognition user interface for allowing a user to input speech commands for controlling telephony services provided by the system, the speech recognition user interface comprising;

(i) an input terminal for receiving an input speech command;

(ii) a memory for storing a plurality of reference models; and

(iii) a comparator for comparing the input speech command with said stored reference models to generate a recognition result; and

executing an operation corresponding to the speech command in dependence upon the recognition result generated by the speech recognition user interface,

wherein each user of the system is identified by a telephone number and an associated identifier, and wherein the executing step comprises the steps of;

receiving data identifying a current status of the telephony system; and

predicting a desired telephony service using the current system status data;

wherein if the user input command identifies a telephony service, then said executing step provides the desired telephony service identified in the input speech command; and

wherein said executing step predicts a desired telephony service using said predicting step and the current system status data, if the input speech command does not identify a desired telephony service.

75. A method according to claim 74, wherein the current system status data comprises, for each user, data indicating:

who the user is currently speaking to, who the user is dialling, who is on hold, who is trying to ring that user, whether that user is playing messages, who has that user on hold, and/or who has that user in a conference.

76. A method according to claim 74 wherein the desired telephony service comprises one of the following services:

setting up a call, transferring a call, holding a call, returning to a call, setting up a conference call, and message selection and relaying.

77. A computer readable medium storing computer executable process steps for controlling a telephony system, the process steps comprising:

steps for providing a speech recognition user interface for allowing a user to input speech commands for controlling the telephony system, comprising;

(i) steps for receiving an input speech command;

(ii) steps for storing a plurality of reference word models; and

(iii) steps for comparing the input speech command with said stored reference word models to generate a recognition result; and

steps for controlling the telephony system in accordance with the input speech command;

wherein said controlling step controls the telephony system so as to reproduce a stored message using the recognition result generated in said comparing step;

wherein said storing step stores said message together with an identifier for identifying the caller that left the message;

wherein said controlling step displays a list of messages to be reproduced upon instruction to reproduce the message identified by said identifier; and

wherein said controlling step comprises predicting, using current system status information, what telephony service is wanted if the user inputs, via said speech recognition user interface, only the identifier of another user.

78. A computer readable medium storing computer executable process steps defining a telephony system, the process steps comprising:

steps for providing a speech recognition user interface allowing a user to input speech commands for controlling telephony services provided by the system, the steps for providing the speech recognition user interface comprising;

(i) steps for receiving an input speech command;

(ii) steps for storing a plurality of reference models; and

(iii) steps for comparing the input speech command with said stored reference models to generate a recognition result; and

steps for executing an operation corresponding to the speech command in response to the generated recognition result,

wherein each user of the system is identified by a telephone number and an associated identifier, and wherein the steps for executing comprise;

steps for receiving data identifying a current status of the telephony system; and

steps for predicting a desired telephony service using the current system status data;

wherein if the user input command identifies a telephony service, then said steps for executing provide the desired telephony service identified in the input speech command; and

wherein said steps for executing predict a desired telephony service using said steps for predicting and the current system status data, if the input speech command does not identify a desired telephony service.

79. A computer readable medium storing computer executable process steps for providing a mail box facility for use with a telephony system, the process steps comprising:

steps for providing a speech recognition user interface for allowing a user to input speech commands for controlling the mail box facility, and for outputting a recognition result based on comparing the input speech commands with pre-stored reference models;

steps for controlling the mail box facility in accordance with an input speech command in response to the recognition result;

steps for storing messages left by callers, when the users are unable to take the calls;

steps for receiving information of the callers via said speech recognition user interface;

steps for reproducing the messages left by the callers identified by the information received in the receiving steps; and

steps for storing a pointer which points to a last messge reproduced in the reproducing steps.

80. A computer executable program for controlling a telephony system, the program comprising:

a code for instructing the telephony system to provide a speech recognition user interface for allowing a user to input speech commands for controlling the telephony system, the speech recognition user interface code comprising;

(i) a code for instructing the telephony system to receive an input speech command;

(ii) a code for instructing the telephony system to store a plurality of reference word models; and

(iii) a code for instructing the telephony system to compare the input speech command with the stored reference word models to generate a recognition result; and

a code for controlling the telephony system in accordance with the input speech command in dependence upon the generated recognition result;

wherein said code for controlling the telephony system further comprises a code to control the telephony system so as to reproduce a stored message using the recognition result generated by said speech recognition user interface;

wherein said code for controlling the telephony system further comprises code for storing said message with an identifier for identifying the caller that left the message;

wherein said code for controlling further comprises code for instructing the telephony system to display a list of messages to be reproduced upon instruction to reproduce the message identified by said identifier; and

wherein said code for controlling further comprises code for instructing the telephony system to predict, using current system status information, what telephony service is wanted if the user inputs, via said speech recognition user interface, only the identifier of another user.

81. A computer executable program for defining a telephony system, the program comprising:

a code for instructing the telephony system to provide a speech recognition user interface for allowing a user to input speech commands for controlling telephony services provided by the system, the speech recognition user interface code comprising;

(i) a code for instructing the telephony system to receive an input speech command;

(ii) a code for instructing the telephony system to store a plurality of reference models; and

(iii) a code for instructing the telephony system to compare the input speech command with the stored reference models to generate a recognition result; and

a code for instructing the telephony system to execute an operation corresponding to the speech command in dependence upon the generated recognition result,

a code for instructing the telephony system to identify each user of the system by a telephone number and an associated identifier, and wherein the execution code comprises;

a code for instructing the telephony system to receive data identifying a current status of the telephony system; and

a code for instructing the telephony system to predict a desired telephony service using the current system status data;

wherein if the user input command identifies a telephony service, then said execution code instructs the telephony system to provide the desired telephony service identified in the input speech command; and

wherein said execution code instructs the telephony system to predict a desired telephony service using said code for predicting and the current system status data, if the input speech command does not identify a desired telephony service.

82. Computer executable program for providing a telephony system, comprising:

a code for instructing the telephony system to provide a speech recognition user interface for allowing a user to input speech commands for controlling the mail box facility, and for outputting a recognition result based on comparing the input speech commands with pre-stored reference models;

a code for controlling the mail box facility in accordance with an input speech command in response to the recognition result;

a code for instructing the telephony system to store messages left by callers, when the users are unable to take the calls;

a code for instructing the telephony system to receive information of the callers via said speech recognition user interface;

a code for instructing the telephony system to reproduce the messages left by the callers identified by the information received by the telephony system; and

a code for instructing the telephony system to store a pointer which points to a last message reproduced by the telephony system.

83. A control system for controlling an information system, comprising:

a speech recognition user interface allowing a user to input speech commands for controlling the information system, said speech recognition user interface comprising;

(i) means for receiving an input speech command;

(ii) means for storing a plurality of reference models;

(iii) means for comparing the input speech command with the stored reference models to generate a recognition result; and

control means, responsive to the recognition result generated by said speech recognition user interface, for controlling the information system in accordance with the input speech command,

wherein said speech recognition user interface is adapted to recognise continuously spoken commands comprising at least one word defining a desired information service,

wherein said speech recognition user interface further comprises means for storing a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands,

wherein said comparing means is operable to compare the input speech command with selected sequences of the reference models, selected in accordance with the stored language model, and

wherein said control means comprises execution means for executing an operation corresponding to the input speech command.

84. A control system for controlling an information system comprising:

a speech recognition user interface allowing a user to input speech commands for controlling the information system, said speech recognition user interface comprising;

(i) an input terminal for receiving an input speech command;

(ii) a memory for storing a plurality of reference models; and

(iii) a comparator for comparing the input speech command with the stored reference models to generate a recognition result; and

a controller, responsive to the recognition result generated by said speech recognition user interface, for controlling the information system in accordance with the input speech command,

wherein said speech recognition user interface is adapted to recognise continuously spoken commands comprising at least one word defining a desired information service,

wherein said speech recognition user interface further comprises a memory for storing a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands,

wherein said comparator compares the input speech command with selected sequences of the reference models, selected in accordance with the stored language model, and

wherein said controller comprises a command executor for executing an operation corresponding to the input speech command.

85. A control system for controlling a telephony system, comprising:

a speech recognition user interface for allowing a user to input speech commands for controlling the telephony system, said speech recognition user interface comprising;

(i) means for receiving an input speech command,

(ii) means for storing a plurality of reference word models,

(iii) means for comparing the input speech command with the stored reference word models to generate a recognition result, and

(iv) means for storing a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands; and

control means, responsive to the recognition result generated by said speech recognition user interface, for controlling the telephony system in accordance with the input speech command,

wherein said comparing means is operable to compare the input speech command with selected sequences of the reference models, selected in accordance with the stored language model, and said control means comprises execution means for executing an operation corresponding to the input speech command.

86. A method of controlling an information system comprising the steps of:

receiving an input speech command;

storing a plurality of reference models;

comparing an input speech command with the stored reference models to generate a recognition result;

in response to the generated recognition result, controlling the information system in accordance with the input speech command; and

storing a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands,

wherein said receiving step receives continuously spoken commands comprising at least one word defining a desired information service;

wherein said comparing step compares the input speech command with selected sequences of the reference models, selected in accordance with the stored language model, and said controlling step includes a step of executing an operation corresponding to the input speech command.

87. A control system for controlling a telephony system, comprising:

a speech recognition user interface that allows a user to input speech commands for controlling the telephony system, wherein the speech recognition user interface receives an input speech command, stores a plurality of reference word models, compares the input speech command with the stored reference word models to generate a recognition result and stores a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands; and

a controller, responsive to the recognition result generated by the speech recognition user interface, that controls the telephony system in accordance with the input speech command,

wherein the speech recognition user interface compares the input speech command with selected sequences of the reference models, selected in accordance with the stored language model, and

wherein the controller executes an operation corresponding to the input speech command.

88. A method of controlling a telephony system, comprising the steps of:

receiving an input speech command;

storing a plurality of reference word models;

storing a language model which defines sequences of the reference models which can be compared with the input speech command, in order to define allowed input speech commands;

comparing the input speech command with selected sequences of the stored reference word models, selected in accordance with the stored language model, to generate a recognition result;

controlling the telephony system in accordance with the input speech command, in response to the generated recognition result; and

executing an operation corresponding to the input speech command.