1. A speech dialog system, comprising: 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; a speech recognition unit configured to receive the enhanced speech signal and generate a recognition result based on the enhanced speech signal; and a control unit configured to receive the analysis signal and control an output unit or an external device based at least in part on the information of the analysis signal.