Modeling pronunciation variation for ASR: A survey of the literature
The focus in automatic speech recognition (ASR) research has gradually shifted from isolated words to conversational speech. Consequently, the amount of pronunciation variation present in the speech under study has gradually increased. Pronunciation variation will deteriorate the performance of an ASR system if it is not well accounted for. This is probably the main reason why research on modeling pronunciation variation for ASR has increased lately. In this contribution, we provide an overview of the publications on this topic, paying particular attention to the papers in this special issue and the papers presented at the Rolduc workshop.1 First, the most important characteristics that distinguish the various studies on pronunciation variation modeling are discussed. Subsequently, the issues of evaluation and comparison are addressed. Particular attention is paid to some of the most important factors that make it difficult to compare the different methods in an objective way. Finally, some conclusions are drawn as to the importance of objective evaluation and the way in which it could be carried out.
pronunciation variation automatic speech recognition