A
speech recognition device having a hidden operator
communication unit and being connectable to a
voice communication system having a user
communication unit, said
speech recognition device comprising a
processing unit and a memory provided for storing
speech recognition data comprising command models and at least one threshold value (T) said
processing unit being provided for
processing speech data, received from said
voice communication system, by scoring said command models against said speech data in order to determine at least one recognition
hypothesis (O), said processing unit being further provided for determining a
confidence score (S) on the basis of said recognition
hypothesis and for weighing said
confidence score against said threshold values in order to accept or reject said received speech data, said device further comprises forwarding means provided for forwarding said speech data to said hidden operator
communication unit in response to said rejection of received speech data, said hidden operator communication unit being provided for generating upon
receipt of said rejection a recognition string based on said received speech data, said hidden operator communication unit being further provided for generating a target
hypothesis (Ot) on the basis of said recognition string generated by said hidden operator communication unit, said device further comprising evaluation means provided for evaluating said target hypothesis with respect to said determined recognition hypothesis and for adapting said stored command models and / or threshold values on the basis of results obtained by said evaluation.