“Robot audition” is a research area that was proposed by Adjunct Professor Kazuhiro Nakadai of Tokyo Institute of Technology (Tokyo Tech) and Professor Hiroshi G. Okuno of Waseda University in 2000. Until then, robots had not been able to recognize voices unless a microphone was near a person’s mouth. Development of “robot ears” began advancing with the idea that robots, like humans, should hear sound with their own ears. The entry barrier for this research area was high, since it involves a combination of signal processing, robotics, and artificial intelligence. However, vigorous activities since its proposal, including the publication of open source software, culminated in its official registration as a research area in 2014 by the IEEE Robotics and Automation Society (RAS), the largest community for robot research.