1. Introduction
For more than a decade a major focus in LVCSR research work have been the yearly U.S. Government sponsored evaluations conducted by NIST. While these evaluations helped the research community to accurately measure the progress in the state-of-the-art in LVCSR and led to impressive improvements in accuracy [17], they also encouraged research sites to pursue “accuracy at any price”. This lead to typical systems running in about 300 times slower than real-time (with some taking up to 2000xRT). As LVCSR technology matured there is now again an increased interest in building faster systems while retaining the gains achieved. This trend is also reflected in the recently initiated DARPA EARS programme which aims at fast transcription of both Broadcast News and Conversational Telephone Speech data.