Abstract:With respect to dialectal-accented speech recognition, dialect-specific lexicon adaptation is anindispensable component to improve the performance. In this paper, a phone-based confusion matrix isadopted to o...Abstract:With respect to dialectal-accented speech recognition, dialect-specific lexicon adaptation is anindispensable component to improve the performance. In this paper, a phone-based confusion matrix isadopted to obtain dialect-specific pronunciation variants. A weighting method, improved context-dependentweighting (ICDW) is proposed to characterize the pronunciation probability precisely by taking both thesurface form left-context-dependency and the base form left-context-dependency into account. To make amuch robust lexicon, a pruning criterion, syllable-dependent pruning (SDP), is also proposed which achievesthe most effective result. In summary, the dialect-specific dialect adaptation reduces a 2.9% absolute anda 3.6% absolute in syllable error rate (SER) respectively on read speech and spontaneous speech fromShanghai-accented speakers.展开更多
A framework for dialectal Chinese speech recognition is proposed and studied, in which a relatively small dialectal Chinese （or in other words Chinese influenced by the native dialect） speech corpus and dialect-rela...A framework for dialectal Chinese speech recognition is proposed and studied, in which a relatively small dialectal Chinese （or in other words Chinese influenced by the native dialect） speech corpus and dialect-related knowledge are adopted to transform a standard Chinese （or Putonghua, abbreviated as PTH） speech recognizer into a dialectal Chinese speech recognizer. Two kinds of knowledge sources are explored： one is expert knowledge and the other is a small dialectal Chinese corpus. These knowledge sources provide information at four levels： phonetic level, lexicon level, language level, and acoustic decoder level. This paper takes Wu dialectal Chinese （WDC） as an example target language. The goal is to establish a WDC speech recognizer from an existing PTH speech recognizer based on the Initial-Final structure of the Chinese language and a study of how dialectal Chinese speakers speak Putonghua. The authors propose to use contextindependent PTH-IF mappings （where IF means either a Chinese Initial or a Chinese Final）, context-independent WDC-IF mappings, and syllable-dependent WDC-IF mappings （obtained from either experts or data）, and combine them with the supervised maximum likelihood linear regression （MLLR） acoustic model adaptation method. To reduce the size of the multipronunciation lexicon introduced by the IF mappings, which might also enlarge the lexicon confusion and hence lead to the performance degradation, a Multi-Pronunciation Expansion （MPE） method based on the accumulated uni-gram probability （AUP） is proposed. In addition, some commonly used WDC words are selected and added to the lexicon. Compared with the original PTH speech recognizer, the resulting WDC speech recognizer achieves 10-18% absolute Character Error Rate （CER） reduction when recognizing WDC, with only a 0.62% CER increase when recognizing PTH. The proposed framework and methods are expected to work not only for Wu dialectal Chinese but also for other dialectal Chinese languages and even other languages.展开更多
文摘Abstract:With respect to dialectal-accented speech recognition, dialect-specific lexicon adaptation is anindispensable component to improve the performance. In this paper, a phone-based confusion matrix isadopted to obtain dialect-specific pronunciation variants. A weighting method, improved context-dependentweighting (ICDW) is proposed to characterize the pronunciation probability precisely by taking both thesurface form left-context-dependency and the base form left-context-dependency into account. To make amuch robust lexicon, a pruning criterion, syllable-dependent pruning (SDP), is also proposed which achievesthe most effective result. In summary, the dialect-specific dialect adaptation reduces a 2.9% absolute anda 3.6% absolute in syllable error rate (SER) respectively on read speech and spontaneous speech fromShanghai-accented speakers.
基金This paper is based upon a study supported by the US National Science Foundation under Grant No.0121285. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author（s） and do not necessarily reflect the views of the National Science Foundation.
文摘A framework for dialectal Chinese speech recognition is proposed and studied, in which a relatively small dialectal Chinese （or in other words Chinese influenced by the native dialect） speech corpus and dialect-related knowledge are adopted to transform a standard Chinese （or Putonghua, abbreviated as PTH） speech recognizer into a dialectal Chinese speech recognizer. Two kinds of knowledge sources are explored： one is expert knowledge and the other is a small dialectal Chinese corpus. These knowledge sources provide information at four levels： phonetic level, lexicon level, language level, and acoustic decoder level. This paper takes Wu dialectal Chinese （WDC） as an example target language. The goal is to establish a WDC speech recognizer from an existing PTH speech recognizer based on the Initial-Final structure of the Chinese language and a study of how dialectal Chinese speakers speak Putonghua. The authors propose to use contextindependent PTH-IF mappings （where IF means either a Chinese Initial or a Chinese Final）, context-independent WDC-IF mappings, and syllable-dependent WDC-IF mappings （obtained from either experts or data）, and combine them with the supervised maximum likelihood linear regression （MLLR） acoustic model adaptation method. To reduce the size of the multipronunciation lexicon introduced by the IF mappings, which might also enlarge the lexicon confusion and hence lead to the performance degradation, a Multi-Pronunciation Expansion （MPE） method based on the accumulated uni-gram probability （AUP） is proposed. In addition, some commonly used WDC words are selected and added to the lexicon. Compared with the original PTH speech recognizer, the resulting WDC speech recognizer achieves 10-18% absolute Character Error Rate （CER） reduction when recognizing WDC, with only a 0.62% CER increase when recognizing PTH. The proposed framework and methods are expected to work not only for Wu dialectal Chinese but also for other dialectal Chinese languages and even other languages.
