  In this paper we report on a system, "SpeechJammer", which can be used to
disturb people's speech. In general, human speech is jammed by giving back to
the speakers their own utterances at a delay of a few hundred milliseconds.
This effect can disturb people without any physical discomfort, and disappears
immediately by stop speaking. Furthermore, this effect does not involve anyone
but the speaker. We utilize this phenomenon and implemented two prototype
versions by combining a direction-sensitive microphone and a
direction-sensitive speaker, enabling the speech of a specific person to be
disturbed. We discuss practical application scenarios of the system, such as
facilitating and controlling discussions. Finally, we argue what system
parameters should be examined in detail in future formal studies based on the
lessons learned from our preliminary study.
