Abstract:
A dialog generation apparatus includes a reception unit configured to receive a first text from a dialog partner, an information storage unit configured to store profile information specific to a person who can be the dialog partner and a fixed-pattern text associated with the person, a presentation unit configured to present the first text to a user, a speech recognition unit configured to perform speech recognition on speech the user has uttered about the first text presented to the user, and generate a speech recognition result showing the content of the speech, a generation unit configured to generate a second text from the profile information about the dialog partner, fixed-pattern text about the dialog partner, and the speech recognition result, and a transmission unit configured to transmit the second text to the dialog partner.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2008-243046, filed Sep. 22, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a dialogue generation apparatus and a dialogue generation method, each utilizing a speech recognition process. 
     2. Description of the Related Art 
     In recent years, many users have come to use various types of dialogue means, such as electronic mail, electronic chat and bulletin board system (BBS). The electronic mail, electronic chat and bulletin board system are text-based dialogue means that achieve an exchange of comparatively short text between the users, unlike telephone and voice chat that are voice-based dialogue means. To use the text-based dialogue means, any user operates a text input interface used as input means, such as a keyboard or the numeric keypad or touch panel provided on a cell phone. In order to enhance the usability of text input, thereby to enable the users to enjoy rhythmical dialogues, text input interfaces based on speech recognition are used in some cases. 
     In the speech recognition process, the user&#39;s speech is converted sequentially into specific standby words on the basis of an acoustic viewpoint and a linguistic viewpoint, thereby generating language text composed of a string of standby words representing the contents of the speech. If the standby words are decreased, the recognition accuracy of individual words increases, but the number of recognizable words decreases. If the standby words are increased, the number of recognizable words increases, but the chances are greater that individual words will be recognized erroneously. Accordingly, to increase the recognition accuracy of the speech recognition process, a method of causing specific words expected to be included in the user&#39;s speech to be recognized preferentially or only the specific words to be recognized has been proposed. Known in the art is not only the continuous speech recognition for recognizing word strings such as so-called “continuous speech,” but also the isolated word recognition for recognizing short words such as operating instructions or keywords input to apparatuses. The isolated word recognition is superior to the continuous speech recognition in terms of recognition accuracy of specific words. 
     With the electronic mail communication apparatus disclosed in JP-A 2002-351791, since a format for writing standby words in an electronic mail text has been determined previously, standby words can be extracted from the received mail according to the format. Therefore, with the electronic mail communication apparatus disclosed in JP-A 2002-351791, high recognition accuracy can be expected by preferentially recognizing the standby words extracted on the basis of the format. In the electronic mail communication apparatus disclosed in JP-A 2002-351791, however, if the specific format is not followed, standby words cannot be written in the electronic mail text. That is, in the electronic mail communication apparatus disclosed in JP-A 2002-351791, since the format of dialogue is limited, the flexibility of dialogue is impaired. 
     With the response data output apparatus disclosed in JP-A 2006-172110, an interrogative sentence is estimated from text data on the basis of a sentence end used at the end of an interrogative sentence. If there are specific paragraphs, including “what time” and “where,” in the estimated interrogative sentence, words representing time and place are recognized preferentially according to the respective paragraphs. If none of specific paragraphs, including “what time” and “where,” are present in the interrogative sentence, words, including “yes” and “no,” are recognized preferentially. Accordingly, with the response data output apparatus disclosed in JP-A 2006-172110, high recognition accuracy can be expected in the user&#39;s speech response to an interrogative sentence. On the other hand, the response data output apparatus does not improve the recognition accuracy in a response to a declarative sentence, an exclamatory sentence, and an imperative sentence other than an interrogative sentence. 
     With the speech-recognition and speech-synthesis apparatus disclosed in JP-A 2003-99089, input text is subjected to morphological analysis and only the words constituting the input text are used as standby words, which enables high recognition accuracy to be expected for the standby words. However, the speech-recognition and speech-synthesis apparatus disclosed in JP-A 2003-99089 has been configured to achieve menu selection, the acquisition of link destination information, and the like, and recognize only the words constituting the input text. That is, a single word or a string of a relatively small number of words has been assumed to be the user&#39;s speech. However, when text (return text) is input, words not included in the input text (e.g., incoming mail) have to be recognized. 
     Note that the accuracy of speech recognition is influenced by environmental factors. If the input speech contains relatively large noise, the content of the input speech may not be fully reflected in the speech recognition result. Consequently, the user needs to input the speech repeatedly or give up inputting the speech. 
     The above-mentioned text-based dialogue means may be used to accomplish periodic dialogue with a family member living in a far-off location or a safety confirmation with an elderly person living alone. However, dialogues achieved by the text-based dialogue means may become flat and dull and hardly last long. 
     BRIEF SUMMARY OF THE INVENTION 
     According to an aspect of the invention, there is provided a dialogue generation apparatus comprising: a reception unit configured to receive a first text from a dialogue partner; an information storage unit configured to store profile information specific to a person who can be the dialogue partner and a fixed-pattern text associated with the person; a presentation unit configured to present the first text to a user; a speech recognition unit configured to perform speech recognition on speech the user has uttered about the first text presented to the user, and generate a speech recognition result showing the content of the speech; a generation unit configured to generate a second text from the profile information about the dialogue partner, fixed-pattern text about the dialogue partner, and the speech recognition result; and a transmission unit configured to transmit the second text to the dialogue partner. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a block diagram showing a dialogue generation apparatus according to a first embodiment; 
         FIG. 2  is a flowchart explaining how the dialogue generation apparatus of  FIG. 1  is operated; 
         FIG. 3  is a diagram showing an example dialogue that may be produced by the dialogue generation apparatus of  FIG. 1 ; 
         FIG. 4  is a diagram showing an example image that the display shown in  FIG. 1  may display; 
         FIG. 5  is a diagram showing another example image that the display shown in  FIG. 1  may display; 
         FIG. 6  is a diagram showing still another example image that the display shown in  FIG. 1  may display; 
         FIG. 7  is a diagram showing further example image that the display of  FIG. 1  may display; 
         FIG. 8  is a diagram showing example content of the speech storage unit shown in  FIG. 1 ; 
         FIG. 9  is a diagram showing example content of the data storage unit shown in  FIG. 1 ; 
         FIG. 10  is a diagram showing an example response that the text the response-text generation unit shown in  FIG. 1  may generate; 
         FIG. 11  is a diagram showing further example content of the speech storage unit shown in  FIG. 1 ; 
         FIG. 12  is a diagram showing another example response text that the response-text generation unit shown in  FIG. 1  may generate; 
         FIG. 13  is a block diagram showing a dialogue generation apparatus according to a second embodiment; 
         FIG. 14  is a diagram showing example content of the use-history storage unit shown in  FIG. 13 ; 
         FIG. 15  is a diagram showing example content of the template storage unit shown in  FIG. 13 ; 
         FIG. 16  is a diagram showing another further content of the template storage unit shown in  FIG. 13 ; and 
         FIG. 17  is a diagram showing an example response text that the response-text generation unit shown in  FIG. 13  may generate. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention will be described with reference to the accompanying drawings. 
     First Embodiment 
     As shown in  FIG. 1 , the dialogue generation apparatus according to a first embodiment of this invention has a text transmitting and receiving unit  101 , a morphological analysis unit  102 , a speech synthesis unit  103 , a speaker  104 , a microphone  105 , a display  106 , a switching instruction unit  107 , a speech storage unit  108 , a isolated word recognition unit  109 , a continuous speech recognition unit  110 , a data storage unit  111 , a response-text generation unit  112 , and a control unit  113 . 
     The text transmitting and receiving unit  101  receives text from a person with whom the user would like to talk (hereinafter called “dialogue partner”). The unit  101  transmits text representing the response to the dialogue partner. (Hereinafter, the text from the dialogue partner will be referred to as “received text”, and the text from user will be referred to as “response text.”) The text is transmitted through a wired network or a wireless network, in compliance with a prescribed communication protocol, such as mail protocol. The text is transmitted in one of various forms, in accordance with the dialogue means used to engage in a dialogue between the user and the dialogue partner. For example, the text may be transmitted as an e-mail, a chat message, or a BBS contributed message. The received text may have an attached file, e.g., an image file and an audio file. Alternatively, the response text may have the attached file. In either case, the text transmitting and receiving unit  101  can receive and transmit the attached file. Further, if the file attached to the received text is text data, the attached file may be managed as similar to the received text. The text transmitting and receiving unit  101  inputs the received text to the morphological analysis unit  102 , speech synthesis unit  103 , display  106  and response-text generation unit  112 , through the control unit  113 . 
     The morphological analysis unit  102  performs morphological analysis on the text it has received from the control unit  113 . Performing the morphological analysis, the morphological analysis unit  102  acquires the words that constitute the received text, and also the linguistic data about each word, such as the pronunciation, part of speech, basic form and conjugated form of the word. The morphological analysis unit  102  sends the results of the morphological analysis performed on the text, back to the control unit  113 . 
     The speech synthesis unit  103  performs speech synthesis on the text received from the control unit  113 , converting the text to an audio signal. The audio signal synthesized by the speech synthesis unit  103  is supplied to the speaker  104 . From the audio signal, the speaker  104  generates speech, which the user may hear. 
     The microphone  105  receives speech the user has uttered and converts the speech into an audio signal. The audio signal is input to the continuous speech recognition unit  110 . Further, the microphone  105  may receive the same speech the user has uttered again and may generate an audio data. The audio data is input via the control unit  113  to the speech storage unit  108  and isolated word recognition unit  109 . 
     The display  106  is, for example, a liquid crystal display (LCD), an electroluminescent display, or the like. The display  106  can display the received text, the continuous speech recognition result, the isolated word recognition result, and the response text. 
     The switching instruction unit  107  receives from the user&#39;s instruction for switching the dialogue generation mode. The switching instruction unit  107  inputs the instruction to the control unit  113 . The method of generating the response text will be explained later in detail. The switching instruction unit  107  can be implemented as, for example, buttons, switches or keys provided on the housing of the dialogue generation apparatus of  FIG. 1 , or buttons displayed on the display  106 . 
     The continuous speech recognition unit  110  performs continuous speech recognition on the speech input to it. More specifically, the continuous speech recognition unit  110  converts the input speech to a linguistic text, based on the acoustic similarity between the input speech and the standby words (i.e., commonly used words) stored in a standby word storage unit (not shown) and on the linguistic reliability. The linguistic text thus obtained is composed of several standby words. The continuous speech recognition unit  110  supplies the speech recognition result, thus obtained, to the control unit  113 . If the continuous speech recognition unit  110  fails to recognize the input speech, it generates a prescribed error message to inform the user of the recognition failure. The error message may be input via the control unit  113  to the speech synthesis unit  103  or the display  106 . Further, the continuous speech recognition unit  110  may input the speech recognition result and a prescribed approval request message via the control unit  113  to the speech synthesis unit  103  or the display  106 . 
     The isolated word recognition unit  109  starts operating when the user, who is dissatisfied with the result of the speech recognition performed by the continuous speech recognition unit  110 , operates the switching instruction unit  107 , inputting a switching instruction. Then, the isolated word recognition unit  109  inputs a message requesting the user to input the same speech again, through the control unit  113 , to the speech synthesis unit  103  or the display  106 . The isolated word recognition unit  109  performs isolated word recognition on the speech the user has input again via the microphone  105 . To be more specific, the isolated word recognition unit  109  converts a part of the input speech to standby words, based on the acoustic similarity between the input speech and the standby words stored in the standby word storage unit (not shown) and on the linguistic reliability. The standby words the isolated word recognition unit  109  processes are more limitative than the standby words the continuous speech recognition unit  110 . The isolated word recognition unit  109  supplies the speech recognition result to the control unit  113 . If the isolated word recognition unit  109  fails to recognize the input speech, it generates a prescribed error message to inform the user of the recognition failure. If the isolated word recognition unit  109  successfully recognizes the input speech, it may input the speech recognition result and a prescribed approval request message via the control unit  113  to the speech synthesis unit  103  or the display  106 . In the speech storage unit  108 , the speech input again and coming from the control unit  113  is stored in association with the result of speech recognition performed by the isolated word recognition unit  109 . 
     In the data storage unit  111 , the profile information specific to persons who can be the dialogue partner, such as mail addresses and birthdays, is stored in association with text (associated text). For example, as shown in  FIG. 9 , the data storage unit  111  stores the mail addresses (profile information) and names or nicknames (associated text) of such persons. Most names and nicknames are proper nouns. Therefore, names and nicknames are difficult to recognize correctly. Nonetheless, the name or nickname of a person is usually used first in a dialogue sentence, as the user addresses that person. In view of this, names and nickname, if stored as associated text, greatly helps to enhance the usability of the apparatus, because it reduces the text inputting time in the speech recognition. Moreover, the proper noun identifying the dialogue partner may be use as a standby word in the continuous speech recognition unit  110  or in the isolated word recognition unit  109 . The user may add or delete words to the data storage unit  111  or to change the content of the data storage unit  111 . The content of the data storage unit  111  is read by the response-text generation unit  112  via the control unit  113 . 
     The response-text generation unit  112  generates a response text by the method that accords with the switching instruction input from the control unit  113 . The method of generating the response text is a method that uses the result of the continuous speech recognition performed by the continuous speech recognition unit  110 , a method that utilizes the result of the isolated word recognition performed by the isolated word recognition unit  109 , or a method that utilizes a voice mail generated from the content of the speech storage unit  108 . Any one of these methods is designated by the switching instruction. For example, to generate a voice mail is to append an audio file to the response text, so that the dialogue partner who has received the response text may refer to the audio file. The response-text generation unit  112  inputs the response text, thus generated, to text transmitting and receiving unit  101  through the control unit  113 . 
     The control unit  113  has a processor such as a central processing unit (CPU). The control unit  113  is configured to control the other components of the dialogue generation apparatus and to supply and receive information and data to and from the other components. For example, the control unit  113  outputs a message informing of the receipt of text, to the speech synthesis unit  103  and the display  106 , causes the display  106  to display the message, causes the speaker  104  to generate an alarm, melody or music, vibrates the dialogue generation apparatus, or causes a light emitting diode (LED) to emit light on and off, thereby informing the user that apparatus has received text from the dialogue partner. 
     How the dialogue generation apparatus of  FIG. 1  operates will be explained with reference to  FIG. 2 . 
     First, the text transmitting and receiving unit  101  receives text, such as an electronic mail, from the dialogue partner (Step S 201 ). Next, the morphological analysis unit  102  performs morphological analysis on the text received in Step S 201  (Step S 202 ). Further, the speech synthesis unit  103  generates a speech signal corresponding to the text received in Step S 201 , from the result of the morphological analysis performed in Step S 202 . The speech signal is supplied to the speaker  104 , which generates the speech represented by the speech signal (Step S 203 ). 
     Hearing the speech generated in Step S 203 , the user produces a response to the microphone  105  (Step S 204 ). The continuous speech recognition unit  110  recognizes the speech the user has uttered in Step S 204 . Thus, speech recognition (i.e., continuous speech recognition) is performed on the speech (Step S 205 ). The display  106  displays the speech recognition result (i.e., continuous speech recognition result) performed in Step S 205 , as is illustrated in  FIG. 4  (Step S 206 ). 
       FIG. 3  shows an example dialogue between the user and an agent (i.e., agent of the dialogue partner), which may be produced as the dialogue generation apparatus of  FIG. 1  performs Steps S 203  to S 206 . In the case shown in  FIG. 3 , the speaker  104  produces the agent&#39;s speech                                ?         GW                                                            (Step S 203 ). In response to the agent&#39;s speech, the user talks,                                                   to the microphone  105 , which generates a speech signal (Step S 204 ). The continuous speech recognition unit  110  performs speech recognition (Step S 205 ). The display  106  displays the speech of                                                   The dialogue generation apparatus is illustrated in  FIG. 3  as a robotic terminal called an “agent.” The dialogue generation apparatus is not limited to such a robotic terminal, nonetheless.
     The user may not be satisfied with the speech recognition result the display  106  displays in Step S 206 . If this is the case, the user operates the switching instruction unit  107 , inputting a switching instruction. That is, if the speech recognition result thus displayed much differs from the speech he or she has uttered as shown in  FIG. 5 , the user can select a response-text selecting method that utilizes the isolated word recognition result. If the user inputs the switching instruction within a predetermined wait time (YES in Step S 207 ), the process will go to Step S 208 . Otherwise (NO in Step S 207 ), the process will go to Step S 214 . 
     In Step S 208 , the user produces the same speech again to the microphone  105 , in response to the agent&#39;s speech uttered by the speaker  104  in Step S 203 . The isolated word recognition unit  109  performs speech recognition (more precisely, isolated word recognition) on the speech input again (Step S 209 ). The control unit  113  causes the speech storage unit  108  to store the speech produced in Step S 208 , in association with the result of speech recognition (i.e., isolated word recognition) performed in Step S 209  (Step S 210 ). In the speech storage unit  108 , the speech data may be stored as associated with the words constituting the speech recognition result, respectively, as shown in  FIG. 8 , or may be stored as associated with the entire speech recognition result, as illustrated in  FIG. 11 . Although the speech input again is shown as text in  FIGS. 8 and 11 , it is actually, for example, a speech file in a prescribed format. Next, the display  106  displays the speech recognition result obtained in Step S 210  (Step S 211 ). 
     The user may not be satisfied with the speech recognition result displayed in Step S 211 . In this case, the user operates the switching instruction unit  107 . That is, if the speech recognition result displayed much differs from the speech he or she has uttered as shown in  FIG. 7 , the user can select a response-text selecting method that utilizes voice mails. If the user inputs the switching instruction within a predetermined wait time (YES in Step S 212 ), the process will go to Step S 213 . In Step S 213 , the response-text generation unit  112  reads the content of the speech storage unit  108  and generates a voice mail from the content. Otherwise (NO in Step S 212 ), the process will go to Step S 214 . 
     In Step S 214 , the response-text generation unit  112  reads the profile information about the dialogue partner and the associated text of the dialogue partner from the data storage unit  111  through the control unit  113 . Then, in Step S 215 , the response-text generation unit  112  generates a response text from the data read in Step S 214  and at least one of the result of the continuous speech recognition performed in Step S 205 , result of the isolated word recognition performed in Step  209  and voice mail generated in Step S 213 . Then, the text transmitting and receiving unit  101  transmits the response text generated in Step S 215  to the dialogue partner (Step S 216 ). 
     In Step S 215 , the response-text generation unit  112  generates the response mail in the form of a response text that designates the mail address of the dialogue partner, i.e., miwako@softobank.jp (see  FIG. 9 ), which has been read in Step S 214 . The response-text generation unit  112  first refers to the text tile of             as the subject of the response mail and then adds “RE:” indicating that the mail is a response, to the head of the text title. Phrase “RE:          ” is thereby generated.
     The response-text generation unit  112  inserts the nickname of the dialogue partner, i.e.,             (see  FIG. 9 ) read in Step S 214  as associated text of the dialogue partner, at the head of the response text. Moreover, the response-text generation unit  112  may add a greeting such as “                              (Happy Birthday!),” to the response text if the day the response text is generated happens to be the birthday of the dialogue partner. Further, the response-text generation unit  112  may insert, in the response text, a message of                              ?         GW                                                                     , adding symbol “&gt;” usually used to denote a reference, to the head of the message. Still further, the response-text generation unit  112  inserts, as a response to the referred part, the result of isolated word recognition performed in Step S 209  and the voice mail generated in Step S 213 . More precisely, the response-text generation unit  112  inserts a speech file from which to generate the phrases input again, i.e.,                                         and                     (see  FIG. 8 ) that correspond, respectively, to the words                               and           that constitute the isolated word recognition result. These phrases are inserted in association with the words constituting the isolated word recognition result, respectively. The method of referring to the speech file is not limited in particular. Nonetheless, any one of the words constituting the isolated word recognition result inserted in the response text may be selected so that the response file associated with the word selected may be reproduced.
     As shown in  FIG. 12 , the response-text generation unit  112  may insert the isolated word recognition result, i.e.,                       (see  FIG. 7 ), as response to the referred part, and may insert the speech input again and corresponding to isolated word recognition result, i.e.,                                                   (see  FIG. 11 ), in association with the isolated word recognition result so that the isolated word recognition result may be referred to. The method of referring to the speech file is not limited in particular. Nonetheless, if the isolated word recognition result, which is inserted in the response text, may be selected so that the speech file associated with the isolated word recognition result selected may be reproduced.
     Moreover, the response-text generation unit  112  may insert the continuous speech recognition performed in Step S 205  or the result of isolated word recognition performed in Step S 209 , as response to the referred part, depending on the method of generating the response text. 
     As described above, the dialogue generation apparatus according to this embodiment is designed to engage in a dialogue, by utilizing the profile information about the dialogue partner and the preset associated text of the dialogue partner. Hence, the dialogue generation apparatus can automatically insert the preset associated text in the response text, without requiring the user&#39;s labor of inputting the preset associated text in the form of speech. This can save the time of inputting data, on the part of the user. Further, the dialogue generation apparatus according to this embodiment generates a response text, using the continuous speech recognition result, the isolated word recognition result, or a voice mail. The apparatus can therefore generate a response text in an appropriate format even if the accuracy of speech recognition is influenced by environmental factors. Thus, the user need not input the speech repeatedly or give up inputting the speech. 
     Second Embodiment 
       FIG. 13  shows the configuration of a dialogue generation apparatus according to a second embodiment of the present invention. As shown in  FIG. 13 , this apparatus differs from the dialogue generation apparatus of  FIG. 1  in that a control unit  118  is provided in place of the control unit  113  and that a communication unit  114 , a use history storage unit  115 , a template storage unit  116 , and a transmission text generation unit  117  are provided in addition. The components identical to those shown in  FIG. 1  are designated by the same reference numbers. The components that characterize the apparatus of  FIG. 13  will be described in the main. 
     The communication unit  114  uses a wireless network or a wired network, achieving communication between the dialogue generation apparatus of  FIG. 13  and a household information appliance that has an interface that can communicate with the dialogue generation apparatus. The household information appliance may be a so-called “digital household appliance” such as TV, video recorder, audio player, or a so-called “white household appliance” such as microwave oven and air conditioner. The communication unit  114  acquires, by communication, use history information from the household appliance. The use history information represents the date and time of use and the type of the household appliance and attribute. The attribute differs from one household appliance to another. If the appliance is a TV or a video recorder, the attribute is the program the user has watched or recorded (e.g., title of the program, etc.). If the appliance is an audio player, the attribute is the music the user has played back (e.g., title of the music, etc.). If the appliance is a microwave oven, the attribute is the cooking menu the user has selected. If the appliance is an air conditioner, the attribute is the temperature the user has selected. The use history information is stored for the household appliance and transmitted to the dialogue generation apparatus of  FIG. 13  at regular intervals or as demanded at the communication unit  114 . The communication unit  114  supplies the use history information to the control unit  118 , which in turn supplies the information to the use history storage unit  115 . The use history storage unit  115  stores the use history information. 
     In the template storage unit  116 , the use history information that may be stored in the use history storage unit  115  and an additional text that may be added to a response in accordance with the use history information are stored in association, as is illustrated in, for example,  FIG. 15 . The history information and the additional text, so stored in the template storage unit  116 , constitute an additional text template. The “additional text” is so formatted that anything other than the user (for example, dialogue generation apparatus of  FIG. 13 ) may recites the user&#39;s way of living, which is estimated from the use history information. The subject of the additional text (e.g., “            (robot)” shown in  FIG. 15 ) is registered, too, in the additional template and inserted, together with the additional text, in the transmission text (later described). In  FIG. 15 , “P” indicates that a random type of the household appliance has been substituted for, “NULL” indicates that no use history information is available for the household information appliance. Further, “★” indicates that an additional text is generated at random. That is, in the instance of  FIG. 15 , the additional text will be “(user)         (attribute)                                       ((user) ate/drank (attribute). Was it good?)” “(attribute)                             ” “(attribute)                   ” or “(attribute)                   ” if the household appliance is a microwave oven. Thus, any additional text related to a household appliance of the same type is generated, in part, at random, so that it may hardly be flat or dull.
     As shown in, for example,  FIG. 16 , the use history information that may be stored in the history storage unit  115  and the subject name associated with the use history information are stored in the template storage unit  116 , constituting a subject name template. The transmission text generation unit  117 , which will be described later, selects one of the subject names stored in the template storage unit  116 , which corresponds to the household appliance used longer than any other type on the day. Note that in  FIG. 16 , “A” indicates that the household appliances differ a little in use time on the day, and “N” indicates that the household appliances are used for a relatively short time on the day. 
     The transmission text generation unit  117  utilizes the use history information read from the history storage unit  115  through the control unit  118  and the additional text template and subject name template, both stored in the control unit  118 . The transmission text generation unit  117  thereby generates a transmission text. More precisely, the transmission text generation unit  117  uses the additional text template, inserting the additional text in the transmission text, and requests the user for a comment on the additional text. If the user inputs speech via the microphone  105 , the transmission text generation unit  117  inserts the result of speech recognition performed on the speech input, as a comment, in the transmission text. The transmission text generation unit  117  inputs the transmission text to the text transmitting and receiving unit  101  through the control unit  118 . The control unit  118  has a processor such as CPU, and controls the other components of the dialogue generation apparatus of  FIG. 13  and receives and supplies information and data. 
     How the transmission text generation unit  117  generates a transmission text will be explained with reference to  FIG. 17 . The transmission text generation unit  117  first reads the use history information stored in the history storage unit  115 , then generates the subject “           TV          (I watched TV today)”, which corresponds to the appliance type “TV” that is used longer than any other appliance on the day, from the subject name template stored in the template storage unit  116 , and finally substitute the subject for the subject name of the transmission text. Further, the transmission text generation unit  117  generates                     that will become the subject of the additional text, from the additional text template (see  FIG. 15 ) that is in the template storage unit  116 , and then inserts the additional text in the transmission text. Next, the transmission text generation unit  117  reads a part of the use history information, e.g., [date=2008, Jun. 21, 12:00-12:30, appliance type=microwave oven, attribute          (salted salmon)],” and inserts, in the transmission text, an additional text “                             (Mum ate salted salmon at launch)” generated by using the additional text template.
     Next, the transmission text generation unit  117  reads a part of the use history information, e.g., [date=2008, Jun. 21, 19:00-19:20, appliance type=microwave oven, attribute            ],” and inserts, in the transmission text, the additional text                     generated by using the additional text template. The transmission text generation unit  117  reads another part of the use history information, e.g., [date=2008, Jun. 21, 19:25-19:30, appliance type=microwave oven, attribute          ],” and inserts, in the transmission text, an additional text “                             ?” generated by using the additional text template.
     When all additional texts concerning the appliance type “microwave oven” are generated as described above, they are displayed on the display  106  of the dialogue generation apparatus of  FIG. 13 , requesting that the user should utter a comment. The user may input speech such as “            (It was good)” to the microphone  105 . The speech input is supplied from the microphone  105  to the continuous speech recognition unit  110 . The continuous speech recognition unit  110  performs speech recognition on the speech. The transmission text generation unit  117  inserts the speech recognition result, i.e., “                   ” in the transmission text. The dialogue generation apparatus may request the user for a comment every time an additional text based on the first time of use history information is inserted, or may request the user for comments on all types of appliances after the additional texts about all appliances have been inserted in the transmission text.
     Next, the transmission text generation unit  117  reads another part of the use history information, e.g., [date=2008, Jun. 21, 19:30-21:15, appliance type=TV, attribute=                     ], and inserts, in the transmission text, an additional text “                             .” generated by using the additional text template, together with the subject of the additional text, i.e.,          . Thus, the dialogue generation apparatus of  FIG. 13  requests the user for a comment when an additional text about the appliance type of “TV” is generated. In response to the request, the user inputs a comment “                   ” to the microphone  105 . The continuous speech recognition unit  110  performs speech recognition on the speech thus input, providing a speech recognition result, i.e.,                    . The transmission text generation unit  117  inserts the speech recognition result, i.e.,                     in the transmission text.
     As has been described, the dialogue generation apparatus according to this embodiment utilizes the use history information about any one of the user&#39;s household appliances, thereby inserting an additional text in a transmission text and ultimately generating a transmission text. The dialogue generation apparatus according to this embodiment can therefore give the user a clue to topics, even in a conversation that may otherwise be most likely flat and dull. This helps the user to keep on talking with the dialogue partner. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. 
     The embodiments described above have been described on the assumption that the texts are all in Japanese. Nevertheless, it should be evident to any person skilled in the art that the present invention can achieve the same advantages if the texts are in any other languages such as English and Chinese. 
     Moreover, various changes and modifications can, of course, be made without departing from the scope and spirit of the present invention.