1. A dialog system comprising: a plurality of dialog modules that receive and process utterances from a speaker and generate synthetic speech or text outputs as responses to the utterances, wherein the plurality of dialog modules include a first dialog module coupled to provide an output to a second dialog module; a controller coupled to the first dialog module, wherein the controller detects an abnormal output of the first dialog module when the first dialog module is processing the utterances in an automatic mode and outputs a signal indicating the abnormal output; and an operator interface coupled to the plurality of dialog modules and the controller, wherein the operator interface receives the signal, wherein the operator interface comprises a mode control for a human agent to control the first dialog module through the controller by correcting the abnormal output and transferring a corrected output to the second dialog module, wherein the corrected output is used in further processing the utterances.