In the second experiment, all the utterances are regarded as `interrupting.' During the 4 days of experiment, 14 subjects talked about the events that all the subjects commonly experienced. We encouraged them to say as many messages as they could. As the result, about 100 parts of speech are recorded. The subjects said that the operations is very intuitive and easy to learn.
We observed the subject's behavior in using the system. Most of the subjects read the written messages first. When they decided to make a reply to a message, they selected the message and listened to it. The users could make messages without listening to the all voices. This fact shows the efficiency of this method.
It also turned out that the messages that are already heard should be easily took off to make the system more usable.