1. A speech dialog system, comprising: a processor; a signal pre-processor unit configured to process a speech input signal and generate an enhanced speech signal and an analysis signal, where the analysis signal comprises information related to one or more non-semantic characteristics of the speech input signal, the signal pre-processor unit outputting the analysis signal for speech dialog control; a speech recognition unit configured to receive the enhanced speech signal and generate a recognition result containing one or more words spoken in the speech input signal based on the enhanced speech signal; a speech output unit configured to output a synthesized speech output in response to the recognition result; and a speech dialog control unit configured to receive the analysis signal and the recognition result, the speech dialog control unit configured to control the speech output unit based upon the received analysis signal, and the speech dialog control unit also configured to control the signal pre-processor unit based upon the on the recognition result.