Decision of response timing for incremental speech recognition with reinforcement learning

In spoken dialog systems, it is important to reduce the delay in generating a response to a user´s utterance. We investigate the use of incremental recognition results which can be obtained from a speech recognition engine before the input utterance ends. To enable the system to respond correctly before the end of the utterance, it is desired to utilize the incremental results effectively, although they are not reliable enough. We formulate this problem as a decision making task, in which the system makes choices iteratively either to answer based on previous observations, or to wait until the next observation. The reinforcement learning can be applied to the problem. As the results of experiments, the users highly evaluate the proposed method which estimate completion time of a user´s utterance by using the results of speech recognition based on mora units.