This book constitutes the refereed proceedings of the Second International Workshop on Spoken Dialogue Systems, IWDS 2010, held in Gotemba, Japan, in October 2010. The 22 session papers presented together with 2 invited keynote talks were carefully reviewed and selected from numerous submissions. The papers deal with topics around Spoken Dialogue Systems for Ambient Environment and discuss common issues of theories, applications, evaluation, limitations, general tools and techniques.