Over the past several decades a need has arisen to enable humans to communicate with machines in order tocontrol their actions or toobtaininformation. | Lawrence R. Rabiner et. Al. Speech Recognition by Machine. 2000 CRC Press LLC. http . Speech Recognition by Machine Lawrence R. Rabiner AT T Labs Research B. H. Juang Bell Laboratories Lucent Technologies Introduction Characterization of Speech Recognition Systems Sources of Variability of Speech Approaches to ASR by Machine The Acoustic-Phonetic Approach 1 Pattern-Matching Approach 2 Artificial Intelligence Approach 3 4 Speech Recognition by Pattern Matching Speech Analysis Pattern Training Pattern Matching Decision Strategy Results of Isolated Word Recognition Connected Word Recognition Performance of Connected Word Recognizers Continuous Speech Recognition Sub-Word Speech Units and Acoustic Modeling Word Modeling From Sub-Word Units Language Modeling Within the Recognizer Performance of Continuous Speech Recognizers Speech Recognition System Issues Robust Speech Recognition 18 Speaker Adaptation 25 Keyword Spotting 26 and Utterance Verification 27 Barge-In Practical Issues in Speech Recognition ASR Applications References Introduction Over the past several decades a need has arisen to enable humans to communicate with machines in order to control their actions or to obtain information. Initial attempts at providing human-machine communications led to the development of the keyboard the mouse the trackball the touch screen and the joy stick. However none of these communication devices provides the richness or the ease of use of speech which has been the most natural form of communication between humans for tens of centuries. Hence a need has arisen to provide a voice interface between humans and machines. This need has been met to a limited extent by speech processing systems which enable a machine to speak speech synthesis systems and which enable a machine to understand speech recognition systems human speech. We concentrate on speech recognition systems in this section. Speech .
