This volume constitutes seleted papers from the 12th International Conference on Text, Speech and Dialogue, TSD 2009, held in Pilsen, Czech Republic, in September 2009. This volume contains a collection of submitted papers presented at the conference which were thoroughly reviewed by three members of the conference reviewing team consisting of more than 40 top specialists in the conference topic areas. A total of 53 accepted papers out of 112 submitted, altogether contributed 127 authors and co-authors, were selected for presentation at the conference by the program committee and then included in this book. Theoretical and more general contributions were presented in common (plenary) sessions. Problem oriented sessions as well as panel discussions then brought together the specialists in limited problem areas with the aim of exchanging knowledge and skills resulting from research projects of all kinds.