8. A speech communication method for enabling a conversation with a conversation partner, said method comprising: tracking a position of the conversation partner, in a normal mode, in response to both of a speech recognition result obtained by recognizing speech of the conversation partner and a image recognition result obtained by recognizing a face of the conversation partner; and continuing the conversation with the conversation partner without tracking including behaviors relying, in the normal mode, on tracking performed by the tracking, the conversation is continued, without tracking, through the speech content of the conversation partner being recognized and matching a predicted response while the speech communication system is in a failure mode as a result of an inability to track the position of the conversation partner.
8. A speech communication method for enabling a conversation with a conversation partner, said method comprising: tracking a position of the conversation partner, in a normal mode, in response to both of a speech recognition result obtained by recognizing speech of the conversation partner and a image recognition result obtained by recognizing a face of the conversation partner; and continuing the conversation with the conversation partner without tracking including behaviors relying, in the normal mode, on tracking performed by the tracking, the conversation is continued, without tracking, through the speech content of the conversation partner being recognized and matching a predicted response while the speech communication system is in a failure mode as a result of an inability to track the position of the conversation partner. 9. The speech communication method according to claim 8 , further comprising: issuing a notification to request the conversation partner to make a response to said notification upon the failure to track the position of the conversation partner by the tracking control unit and the speech contents of the conversation partner not matching the predicted response; repeating the notification a prescribed number of times when the response to said notification is not received from the conversation partner; and terminating the conversation when the response to said notification is not received from the conversation partner after the notification is repeated the prescribed number of times.